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feat(core): Add option to enhance the fetch error message#18466

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Merged
JPeer264 merged 10 commits into from
Jan 12, 2026
Merged

feat(core): Add option to enhance the fetch error message #18466

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aff7d32
feat(core): Add option to enhance the fetch error message
JPeer264 Dec 10, 2025
2fae839
fixup! feat(core): Add option to enhance the fetch error message
JPeer264 Dec 15, 2025
8f4e49f
Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…
JPeer264 Dec 18, 2025
56f4d61
Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…
JPeer264 Dec 18, 2025
acb01af
Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…
JPeer264 Dec 18, 2025
0006201
Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…
JPeer264 Dec 18, 2025
f0e0bc6
Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…
JPeer264 Dec 18, 2025
52fafca
Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…
JPeer264 Dec 18, 2025
1a07ef6
fixup! feat(core): Add option to enhance the fetch error message
JPeer264 Jan 9, 2026
254b83c
fixup! feat(core): Add option to enhance the fetch error message
JPeer264 Jan 12, 2026
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16 changes: 8 additions & 8 deletions .size-limit.js
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -8,7 +8,7 @@ module.exports = [
path: 'packages/browser/build/npm/esm/prod/index.js',
import: createImport('init'),
gzip: true,
limit: '25 KB',
limit: '25.5 KB',
},
{
name: '@sentry/browser - with treeshaking flags',
Expand DownExpand Up@@ -148,7 +148,7 @@ module.exports = [
import: createImport('init', 'ErrorBoundary', 'reactRouterV6BrowserTracingIntegration'),
ignore: ['react/jsx-runtime'],
gzip: true,
limit: '44 KB',
limit: '44.5 KB',
},
// Vue SDK (ESM)
{
Expand All@@ -171,20 +171,20 @@ module.exports = [
path: 'packages/svelte/build/esm/index.js',
import: createImport('init'),
gzip: true,
limit: '25 KB',
limit: '25.5 KB',
},
// Browser CDN bundles
{
name: 'CDN Bundle',
path: createCDNPath('bundle.min.js'),
gzip: true,
limit: '27.5 KB',
limit: '28 KB',
},
{
name: 'CDN Bundle (incl. Tracing)',
path: createCDNPath('bundle.tracing.min.js'),
gzip: true,
limit: '42.5 KB',
limit: '43 KB',
},
{
name: 'CDN Bundle (incl. Tracing, Replay)',
Expand DownExpand Up@@ -234,7 +234,7 @@ module.exports = [
import: createImport('init'),
ignore: ['next/router', 'next/constants'],
gzip: true,
limit: '46.5 KB',
limit: '47 KB',
},
// SvelteKit SDK (ESM)
{
Expand All@@ -243,7 +243,7 @@ module.exports = [
import: createImport('init'),
ignore: ['$app/stores'],
gzip: true,
limit: '42.5 KB',
limit: '43 KB',
},
// Node-Core SDK (ESM)
{
Expand All@@ -261,7 +261,7 @@ module.exports = [
import: createImport('init'),
ignore: [...builtinModules, ...nodePrefixedBuiltinModules],
gzip: true,
limit: '162.5 KB',
limit: '163 KB',
},
{
name: '@sentry/node - without tracing',
Expand Down
8 changes: 8 additions & 0 deletions dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/init.js
View file
Open in desktop
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
dsn: 'https://public@dsn.ingest.sentry.io/1337',
enhanceFetchErrorMessages: false,
});
49 changes: 49 additions & 0 deletions dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/subject.js
View file
Open in desktop
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
// Based on possible TypeError exceptions from https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch

// Network error (e.g. ad-blocked, offline, page does not exist, ...)
window.networkError = () => {
fetch('http://sentry-test-external.io/does-not-exist');
};

window.networkErrorSubdomain = () => {
fetch('http://subdomain.sentry-test-external.io/does-not-exist');
};

window.networkErrorWithPort = () => {
fetch('http://sentry-test-external.io:3000/does-not-exist');
};

// Invalid header also produces TypeError
window.invalidHeaderName = () => {
fetch('http://sentry-test-external.io/invalid-header-name', { headers: { 'C ontent-Type': 'text/xml' } });
};

// Invalid header value also produces TypeError
window.invalidHeaderValue = () => {
fetch('http://sentry-test-external.io/invalid-header-value', { headers: ['Content-Type', 'text/html', 'extra'] });
};

// Invalid URL scheme
window.invalidUrlScheme = () => {
fetch('blub://sentry-test-external.io/invalid-scheme');
};

// URL includes credentials
window.credentialsInUrl = () => {
fetch('https://user:password@sentry-test-external.io/credentials-in-url');
};

// Invalid mode
window.invalidMode = () => {
fetch('https://sentry-test-external.io/invalid-mode', { mode: 'navigate' });
};

// Invalid request method
window.invalidMethod = () => {
fetch('http://sentry-test-external.io/invalid-method', { method: 'CONNECT' });
};

// No-cors mode with cors-required method
window.noCorsMethod = () => {
fetch('http://sentry-test-external.io/no-cors-method', { mode: 'no-cors', method: 'PUT' });
};
113 changes: 113 additions & 0 deletions dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/test.ts
View file
Open in desktop
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,113 @@
import { expect } from '@playwright/test';
import { sentryTest } from '../../../utils/fixtures';
import { envelopeRequestParser, waitForErrorRequest } from '../../../utils/helpers';

sentryTest(
'enhanceFetchErrorMessages: false: enhances error for Sentry while preserving original',
async ({ getLocalTestUrl, page, browserName }) => {
const url = await getLocalTestUrl({ testDir: __dirname });
const reqPromise = waitForErrorRequest(page);
const pageErrorPromise = new Promise<string>(resolve => {
page.on('pageerror', error => {
resolve(error.message);
});
});

await page.goto(url);
await page.evaluate('networkError()');

const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
const eventData = envelopeRequestParser(req);
const originalErrorMap: Record<string, string> = {
chromium: 'Failed to fetch',
webkit: 'Load failed',
firefox: 'NetworkError when attempting to fetch resource.',
};

const originalError = originalErrorMap[browserName];

expect(pageErrorMessage).toContain(originalError);
expect(pageErrorMessage).not.toContain('sentry-test-external.io');

expect(eventData.exception?.values).toHaveLength(1);
expect(eventData.exception?.values?.[0]).toMatchObject({
type: 'TypeError',
value: originalError,
mechanism: {
handled: false,
type: 'auto.browser.global_handlers.onunhandledrejection',
},
});
},
);

sentryTest(
'enhanceFetchErrorMessages: false: enhances subdomain errors',
async ({ getLocalTestUrl, page, browserName }) => {
const url = await getLocalTestUrl({ testDir: __dirname });
const reqPromise = waitForErrorRequest(page);
const pageErrorPromise = new Promise<string>(resolve => page.on('pageerror', error => resolve(error.message)));

await page.goto(url);
await page.evaluate('networkErrorSubdomain()');

const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
const eventData = envelopeRequestParser(req);

const originalErrorMap: Record<string, string> = {
chromium: 'Failed to fetch',
webkit: 'Load failed',
firefox: 'NetworkError when attempting to fetch resource.',
};

const originalError = originalErrorMap[browserName];

expect(pageErrorMessage).toContain(originalError);
expect(pageErrorMessage).not.toContain('subdomain.sentry-test-external.io');
expect(eventData.exception?.values).toHaveLength(1);
expect(eventData.exception?.values?.[0]).toMatchObject({
type: 'TypeError',
value: originalError,
mechanism: {
handled: false,
type: 'auto.browser.global_handlers.onunhandledrejection',
},
});
},
);

sentryTest(
'enhanceFetchErrorMessages: false: includes port in hostname',
async ({ getLocalTestUrl, page, browserName }) => {
const url = await getLocalTestUrl({ testDir: __dirname });
const reqPromise = waitForErrorRequest(page);

const pageErrorPromise = new Promise<string>(resolve => page.on('pageerror', error => resolve(error.message)));

await page.goto(url);
await page.evaluate('networkErrorWithPort()');

const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
const eventData = envelopeRequestParser(req);

const originalErrorMap: Record<string, string> = {
chromium: 'Failed to fetch',
webkit: 'Load failed',
firefox: 'NetworkError when attempting to fetch resource.',
};

const originalError = originalErrorMap[browserName];

expect(pageErrorMessage).toContain(originalError);
expect(pageErrorMessage).not.toContain('sentry-test-external.io:3000');
expect(eventData.exception?.values).toHaveLength(1);
expect(eventData.exception?.values?.[0]).toMatchObject({
type: 'TypeError',
value: originalError,
mechanism: {
handled: false,
type: 'auto.browser.global_handlers.onunhandledrejection',
},
});
},
);
8 changes: 8 additions & 0 deletions ...ckages/browser-integration-tests/suites/errors/fetch-enhance-messages-report-only/init.js
View file
Open in desktop
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
dsn: 'https://public@dsn.ingest.sentry.io/1337',
enhanceFetchErrorMessages: 'report-only',
});
49 changes: 49 additions & 0 deletions ...ges/browser-integration-tests/suites/errors/fetch-enhance-messages-report-only/subject.js
View file
Open in desktop
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
// Based on possible TypeError exceptions from https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch

// Network error (e.g. ad-blocked, offline, page does not exist, ...)
window.networkError = () => {
fetch('http://sentry-test-external.io/does-not-exist');
};

window.networkErrorSubdomain = () => {
fetch('http://subdomain.sentry-test-external.io/does-not-exist');
};

window.networkErrorWithPort = () => {
fetch('http://sentry-test-external.io:3000/does-not-exist');
};

// Invalid header also produces TypeError
window.invalidHeaderName = () => {
fetch('http://sentry-test-external.io/invalid-header-name', { headers: { 'C ontent-Type': 'text/xml' } });
};

// Invalid header value also produces TypeError
window.invalidHeaderValue = () => {
fetch('http://sentry-test-external.io/invalid-header-value', { headers: ['Content-Type', 'text/html', 'extra'] });
};

// Invalid URL scheme
window.invalidUrlScheme = () => {
fetch('blub://sentry-test-external.io/invalid-scheme');
};

// URL includes credentials
window.credentialsInUrl = () => {
fetch('https://user:password@sentry-test-external.io/credentials-in-url');
};

// Invalid mode
window.invalidMode = () => {
fetch('https://sentry-test-external.io/invalid-mode', { mode: 'navigate' });
};

// Invalid request method
window.invalidMethod = () => {
fetch('http://sentry-test-external.io/invalid-method', { method: 'CONNECT' });
};

// No-cors mode with cors-required method
window.noCorsMethod = () => {
fetch('http://sentry-test-external.io/no-cors-method', { mode: 'no-cors', method: 'PUT' });
};
Loading
Loading
, 'i'); if (__m === '*' || __re.test(location.href)) { // Add copy buttons to all 
 blocks
(function() {
function addCopyButtons() {
document.querySelectorAll('pre code').forEach(function(codeBlock) {
if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;
codeBlock.parentElement.setAttribute('data-copy-added', 'true');
var btn = document.createElement('button');
btn.textContent = 'Copy';
btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';
btn.onmouseover = function() { this.style.opacity = '1'; };
btn.onmouseout = function() { this.style.opacity = '0.7'; };
btn.onclick = function() {
navigator.clipboard.writeText(codeBlock.textContent).then(function() {
btn.textContent = 'Copied!';
setTimeout(function() { btn.textContent = 'Copy'; }, 1500);
});
};
codeBlock.parentElement.style.position = 'relative';
codeBlock.parentElement.appendChild(btn);
});
}
addCopyButtons();
// Re-run on dynamic content
var observer = new MutationObserver(addCopyButtons);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '
feat(core): Add option to enhance the fetch error message by JPeer264 · Pull Request #18466 · getsentry/sentry-javascript · GitHub
Skip to content
feat(core): Add option to enhance the fetch error message#18466

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privacy statement. We’ll occasionally send you account related emails.

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to your account

 Merged

JPeer264
merged 10 commits into

from

Jan 12, 2026
 Merged


feat(core): Add option to enhance the fetch error message
#18466
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aff7d32

feat(core): Add option to enhance the fetch error message


JPeer264 Dec 10, 2025
2fae839

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Dec 15, 2025
8f4e49f

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
56f4d61

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
acb01af

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
0006201

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
f0e0bc6

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
52fafca

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
1a07ef6

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Jan 9, 2026
254b83c

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Jan 12, 2026

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16 changes: 8 additions & 8 deletions
.size-limit.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -8,7 +8,7 @@ module.exports = [
 path: 'packages/browser/build/npm/esm/prod/index.js',
 import: createImport('init'),
 gzip: true,
 limit: '25 KB',
 limit: '25.5 KB',
 },
 {
 name: '@sentry/browser - with treeshaking flags',
Expand DownExpand Up@@ -148,7 +148,7 @@ module.exports = [
 import: createImport('init', 'ErrorBoundary', 'reactRouterV6BrowserTracingIntegration'),
 ignore: ['react/jsx-runtime'],
 gzip: true,
 limit: '44 KB',
 limit: '44.5 KB',
 },
 // Vue SDK (ESM)
 {
Expand All@@ -171,20 +171,20 @@ module.exports = [
 path: 'packages/svelte/build/esm/index.js',
 import: createImport('init'),
 gzip: true,
 limit: '25 KB',
 limit: '25.5 KB',
 },
 // Browser CDN bundles
 {
 name: 'CDN Bundle',
 path: createCDNPath('bundle.min.js'),
 gzip: true,
 limit: '27.5 KB',
 limit: '28 KB',
 },
 {
 name: 'CDN Bundle (incl. Tracing)',
 path: createCDNPath('bundle.tracing.min.js'),
 gzip: true,
 limit: '42.5 KB',
 limit: '43 KB',
 },
 {
 name: 'CDN Bundle (incl. Tracing, Replay)',
Expand DownExpand Up@@ -234,7 +234,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['next/router', 'next/constants'],
 gzip: true,
 limit: '46.5 KB',
 limit: '47 KB',
 },
 // SvelteKit SDK (ESM)
 {
Expand All@@ -243,7 +243,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['$app/stores'],
 gzip: true,
 limit: '42.5 KB',
 limit: '43 KB',
 },
 // Node-Core SDK (ESM)
 {
Expand All@@ -261,7 +261,7 @@ module.exports = [
 import: createImport('init'),
 ignore: [...builtinModules, ...nodePrefixedBuiltinModules],
 gzip: true,
 limit: '162.5 KB',
 limit: '163 KB',
 },
 {
 name: '@sentry/node - without tracing',
Expand Down

8 changes: 8 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/init.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 enhanceFetchErrorMessages: false,
});

49 changes: 49 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/subject.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
// Based on possible TypeError exceptions from https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch

// Network error (e.g. ad-blocked, offline, page does not exist, ...)
window.networkError = () => {
 fetch('http://sentry-test-external.io/does-not-exist');
};

window.networkErrorSubdomain = () => {
 fetch('http://subdomain.sentry-test-external.io/does-not-exist');
};

window.networkErrorWithPort = () => {
 fetch('http://sentry-test-external.io:3000/does-not-exist');
};

// Invalid header also produces TypeError
window.invalidHeaderName = () => {
 fetch('http://sentry-test-external.io/invalid-header-name', { headers: { 'C ontent-Type': 'text/xml' } });
};

// Invalid header value also produces TypeError
window.invalidHeaderValue = () => {
 fetch('http://sentry-test-external.io/invalid-header-value', { headers: ['Content-Type', 'text/html', 'extra'] });
};

// Invalid URL scheme
window.invalidUrlScheme = () => {
 fetch('blub://sentry-test-external.io/invalid-scheme');
};

// URL includes credentials
window.credentialsInUrl = () => {
 fetch('https://user:password@sentry-test-external.io/credentials-in-url');
};

// Invalid mode
window.invalidMode = () => {
 fetch('https://sentry-test-external.io/invalid-mode', { mode: 'navigate' });
};

// Invalid request method
window.invalidMethod = () => {
 fetch('http://sentry-test-external.io/invalid-method', { method: 'CONNECT' });
};

// No-cors mode with cors-required method
window.noCorsMethod = () => {
 fetch('http://sentry-test-external.io/no-cors-method', { mode: 'no-cors', method: 'PUT' });
};

113 changes: 113 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/test.ts

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Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,113 @@
import { expect } from '@playwright/test';
import { sentryTest } from '../../../utils/fixtures';
import { envelopeRequestParser, waitForErrorRequest } from '../../../utils/helpers';

sentryTest(
 'enhanceFetchErrorMessages: false: enhances error for Sentry while preserving original',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);
 const pageErrorPromise = new Promise<string>(resolve => {
 page.on('pageerror', error => {
 resolve(error.message);
 });
 });

 await page.goto(url);
 await page.evaluate('networkError()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);
 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('sentry-test-external.io');

 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

sentryTest(
 'enhanceFetchErrorMessages: false: enhances subdomain errors',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);
 const pageErrorPromise = new Promise<string>(resolve => page.on('pageerror', error => resolve(error.message)));

 await page.goto(url);
 await page.evaluate('networkErrorSubdomain()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);

 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('subdomain.sentry-test-external.io');
 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

sentryTest(
 'enhanceFetchErrorMessages: false: includes port in hostname',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);

 const pageErrorPromise = new Promise<string>(resolve => page.on('pageerror', error => resolve(error.message)));

 await page.goto(url);
 await page.evaluate('networkErrorWithPort()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);

 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('sentry-test-external.io:3000');
 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

8 changes: 8 additions & 0 deletions
...ckages/browser-integration-tests/suites/errors/fetch-enhance-messages-report-only/init.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 enhanceFetchErrorMessages: 'report-only',
});

49 changes: 49 additions & 0 deletions
...ges/browser-integration-tests/suites/errors/fetch-enhance-messages-report-only/subject.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
// Based on possible TypeError exceptions from https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch

// Network error (e.g. ad-blocked, offline, page does not exist, ...)
window.networkError = () => {
 fetch('http://sentry-test-external.io/does-not-exist');
};

window.networkErrorSubdomain = () => {
 fetch('http://subdomain.sentry-test-external.io/does-not-exist');
};

window.networkErrorWithPort = () => {
 fetch('http://sentry-test-external.io:3000/does-not-exist');
};

// Invalid header also produces TypeError
window.invalidHeaderName = () => {
 fetch('http://sentry-test-external.io/invalid-header-name', { headers: { 'C ontent-Type': 'text/xml' } });
};

// Invalid header value also produces TypeError
window.invalidHeaderValue = () => {
 fetch('http://sentry-test-external.io/invalid-header-value', { headers: ['Content-Type', 'text/html', 'extra'] });
};

// Invalid URL scheme
window.invalidUrlScheme = () => {
 fetch('blub://sentry-test-external.io/invalid-scheme');
};

// URL includes credentials
window.credentialsInUrl = () => {
 fetch('https://user:password@sentry-test-external.io/credentials-in-url');
};

// Invalid mode
window.invalidMode = () => {
 fetch('https://sentry-test-external.io/invalid-mode', { mode: 'navigate' });
};

// Invalid request method
window.invalidMethod = () => {
 fetch('http://sentry-test-external.io/invalid-method', { method: 'CONNECT' });
};

// No-cors mode with cors-required method
window.noCorsMethod = () => {
 fetch('http://sentry-test-external.io/no-cors-method', { mode: 'no-cors', method: 'PUT' });
};
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Force GitHub README to respect dark mode
(function() {
var style = document.createElement('style');
style.textContent = '
.markdown-body {
color-scheme: dark light;
}
.markdown-body pre { background: #161b22 !important; }
.markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }
.markdown-body table th, .markdown-body table td { border-color: #30363d !important; }
.markdown-body img { background: #0d1117; }
.markdown-body blockquote { border-left-color: #8b949e; }
.markdown-body hr { border-color: #30363d; }
';
document.head.appendChild(style);
})();
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
feat(core): Add option to enhance the fetch error message by JPeer264 · Pull Request #18466 · getsentry/sentry-javascript · GitHub
Skip to content
feat(core): Add option to enhance the fetch error message#18466

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 Merged

JPeer264
merged 10 commits into

from

Jan 12, 2026
 Merged


feat(core): Add option to enhance the fetch error message
#18466
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aff7d32

feat(core): Add option to enhance the fetch error message


JPeer264 Dec 10, 2025
2fae839

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Dec 15, 2025
8f4e49f

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
56f4d61

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
acb01af

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
0006201

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
f0e0bc6

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
52fafca

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
1a07ef6

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Jan 9, 2026
254b83c

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Jan 12, 2026

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16 changes: 8 additions & 8 deletions
.size-limit.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -8,7 +8,7 @@ module.exports = [
 path: 'packages/browser/build/npm/esm/prod/index.js',
 import: createImport('init'),
 gzip: true,
 limit: '25 KB',
 limit: '25.5 KB',
 },
 {
 name: '@sentry/browser - with treeshaking flags',
Expand DownExpand Up@@ -148,7 +148,7 @@ module.exports = [
 import: createImport('init', 'ErrorBoundary', 'reactRouterV6BrowserTracingIntegration'),
 ignore: ['react/jsx-runtime'],
 gzip: true,
 limit: '44 KB',
 limit: '44.5 KB',
 },
 // Vue SDK (ESM)
 {
Expand All@@ -171,20 +171,20 @@ module.exports = [
 path: 'packages/svelte/build/esm/index.js',
 import: createImport('init'),
 gzip: true,
 limit: '25 KB',
 limit: '25.5 KB',
 },
 // Browser CDN bundles
 {
 name: 'CDN Bundle',
 path: createCDNPath('bundle.min.js'),
 gzip: true,
 limit: '27.5 KB',
 limit: '28 KB',
 },
 {
 name: 'CDN Bundle (incl. Tracing)',
 path: createCDNPath('bundle.tracing.min.js'),
 gzip: true,
 limit: '42.5 KB',
 limit: '43 KB',
 },
 {
 name: 'CDN Bundle (incl. Tracing, Replay)',
Expand DownExpand Up@@ -234,7 +234,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['next/router', 'next/constants'],
 gzip: true,
 limit: '46.5 KB',
 limit: '47 KB',
 },
 // SvelteKit SDK (ESM)
 {
Expand All@@ -243,7 +243,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['$app/stores'],
 gzip: true,
 limit: '42.5 KB',
 limit: '43 KB',
 },
 // Node-Core SDK (ESM)
 {
Expand All@@ -261,7 +261,7 @@ module.exports = [
 import: createImport('init'),
 ignore: [...builtinModules, ...nodePrefixedBuiltinModules],
 gzip: true,
 limit: '162.5 KB',
 limit: '163 KB',
 },
 {
 name: '@sentry/node - without tracing',
Expand Down

8 changes: 8 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/init.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 enhanceFetchErrorMessages: false,
});

49 changes: 49 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/subject.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
// Based on possible TypeError exceptions from https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch

// Network error (e.g. ad-blocked, offline, page does not exist, ...)
window.networkError = () => {
 fetch('http://sentry-test-external.io/does-not-exist');
};

window.networkErrorSubdomain = () => {
 fetch('http://subdomain.sentry-test-external.io/does-not-exist');
};

window.networkErrorWithPort = () => {
 fetch('http://sentry-test-external.io:3000/does-not-exist');
};

// Invalid header also produces TypeError
window.invalidHeaderName = () => {
 fetch('http://sentry-test-external.io/invalid-header-name', { headers: { 'C ontent-Type': 'text/xml' } });
};

// Invalid header value also produces TypeError
window.invalidHeaderValue = () => {
 fetch('http://sentry-test-external.io/invalid-header-value', { headers: ['Content-Type', 'text/html', 'extra'] });
};

// Invalid URL scheme
window.invalidUrlScheme = () => {
 fetch('blub://sentry-test-external.io/invalid-scheme');
};

// URL includes credentials
window.credentialsInUrl = () => {
 fetch('https://user:password@sentry-test-external.io/credentials-in-url');
};

// Invalid mode
window.invalidMode = () => {
 fetch('https://sentry-test-external.io/invalid-mode', { mode: 'navigate' });
};

// Invalid request method
window.invalidMethod = () => {
 fetch('http://sentry-test-external.io/invalid-method', { method: 'CONNECT' });
};

// No-cors mode with cors-required method
window.noCorsMethod = () => {
 fetch('http://sentry-test-external.io/no-cors-method', { mode: 'no-cors', method: 'PUT' });
};

113 changes: 113 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/test.ts

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Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,113 @@
import { expect } from '@playwright/test';
import { sentryTest } from '../../../utils/fixtures';
import { envelopeRequestParser, waitForErrorRequest } from '../../../utils/helpers';

sentryTest(
 'enhanceFetchErrorMessages: false: enhances error for Sentry while preserving original',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);
 const pageErrorPromise = new Promise<string>(resolve => {
 page.on('pageerror', error => {
 resolve(error.message);
 });
 });

 await page.goto(url);
 await page.evaluate('networkError()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);
 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('sentry-test-external.io');

 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

sentryTest(
 'enhanceFetchErrorMessages: false: enhances subdomain errors',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);
 const pageErrorPromise = new Promise<string>(resolve => page.on('pageerror', error => resolve(error.message)));

 await page.goto(url);
 await page.evaluate('networkErrorSubdomain()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);

 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('subdomain.sentry-test-external.io');
 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

sentryTest(
 'enhanceFetchErrorMessages: false: includes port in hostname',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);

 const pageErrorPromise = new Promise<string>(resolve => page.on('pageerror', error => resolve(error.message)));

 await page.goto(url);
 await page.evaluate('networkErrorWithPort()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);

 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('sentry-test-external.io:3000');
 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

8 changes: 8 additions & 0 deletions
...ckages/browser-integration-tests/suites/errors/fetch-enhance-messages-report-only/init.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 enhanceFetchErrorMessages: 'report-only',
});

49 changes: 49 additions & 0 deletions
...ges/browser-integration-tests/suites/errors/fetch-enhance-messages-report-only/subject.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
// Based on possible TypeError exceptions from https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch

// Network error (e.g. ad-blocked, offline, page does not exist, ...)
window.networkError = () => {
 fetch('http://sentry-test-external.io/does-not-exist');
};

window.networkErrorSubdomain = () => {
 fetch('http://subdomain.sentry-test-external.io/does-not-exist');
};

window.networkErrorWithPort = () => {
 fetch('http://sentry-test-external.io:3000/does-not-exist');
};

// Invalid header also produces TypeError
window.invalidHeaderName = () => {
 fetch('http://sentry-test-external.io/invalid-header-name', { headers: { 'C ontent-Type': 'text/xml' } });
};

// Invalid header value also produces TypeError
window.invalidHeaderValue = () => {
 fetch('http://sentry-test-external.io/invalid-header-value', { headers: ['Content-Type', 'text/html', 'extra'] });
};

// Invalid URL scheme
window.invalidUrlScheme = () => {
 fetch('blub://sentry-test-external.io/invalid-scheme');
};

// URL includes credentials
window.credentialsInUrl = () => {
 fetch('https://user:password@sentry-test-external.io/credentials-in-url');
};

// Invalid mode
window.invalidMode = () => {
 fetch('https://sentry-test-external.io/invalid-mode', { mode: 'navigate' });
};

// Invalid request method
window.invalidMethod = () => {
 fetch('http://sentry-test-external.io/invalid-method', { method: 'CONNECT' });
};

// No-cors mode with cors-required method
window.noCorsMethod = () => {
 fetch('http://sentry-test-external.io/no-cors-method', { mode: 'no-cors', method: 'PUT' });
};
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Highlight search terms from Google/DuckDuckGo/Bing referrer
(function() {
var ref = document.referrer;
var terms = [];
if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {
var url = new URL(ref);
var q = url.searchParams.get('q') || url.searchParams.get('p');
if (q) {
terms = q.split(/\s+/).filter(function(t) { return t.length > 2; });
}
}
if (terms.length === 0) return;
var style = document.createElement('style');
style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';
document.head.appendChild(style);
function highlight(node) {
if (node.nodeType === 3) { // text node
var text = node.textContent;
var found = false;
terms.forEach(function(term) {
var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\]\\]/g, '\\') + ')', 'gi');
if (regex.test(text)) {
found = true;
var frag = document.createDocumentFragment();
var parts = text.split(regex);
parts.forEach(function(part, i) {
if (i % 2 === 0) {
frag.appendChild(document.createTextNode(part));
} else {
var span = document.createElement('span');
span.className = 'userscript-highlight';
span.textContent = part;
frag.appendChild(span);
}
});
node.parentNode.replaceChild(frag, node);
}
});
} else if (node.nodeType === 1 && node.childNodes) { // element
var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];
if (!skipTags.includes(node.tagName)) {
Array.from(node.childNodes).forEach(highlight);
}
}
}
highlight(document.body);
// Re-highlight on dynamic content
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1 || node.nodeType === 3) highlight(node);
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
feat(core): Add option to enhance the fetch error message by JPeer264 · Pull Request #18466 · getsentry/sentry-javascript · GitHub
Skip to content
feat(core): Add option to enhance the fetch error message#18466

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

 Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Merged

JPeer264
merged 10 commits into

from

Jan 12, 2026
 Merged


feat(core): Add option to enhance the fetch error message
#18466
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aff7d32

feat(core): Add option to enhance the fetch error message


JPeer264 Dec 10, 2025
2fae839

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Dec 15, 2025
8f4e49f

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
56f4d61

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
acb01af

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
0006201

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
f0e0bc6

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
52fafca

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
1a07ef6

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Jan 9, 2026
254b83c

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Jan 12, 2026

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16 changes: 8 additions & 8 deletions
.size-limit.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -8,7 +8,7 @@ module.exports = [
 path: 'packages/browser/build/npm/esm/prod/index.js',
 import: createImport('init'),
 gzip: true,
 limit: '25 KB',
 limit: '25.5 KB',
 },
 {
 name: '@sentry/browser - with treeshaking flags',
Expand DownExpand Up@@ -148,7 +148,7 @@ module.exports = [
 import: createImport('init', 'ErrorBoundary', 'reactRouterV6BrowserTracingIntegration'),
 ignore: ['react/jsx-runtime'],
 gzip: true,
 limit: '44 KB',
 limit: '44.5 KB',
 },
 // Vue SDK (ESM)
 {
Expand All@@ -171,20 +171,20 @@ module.exports = [
 path: 'packages/svelte/build/esm/index.js',
 import: createImport('init'),
 gzip: true,
 limit: '25 KB',
 limit: '25.5 KB',
 },
 // Browser CDN bundles
 {
 name: 'CDN Bundle',
 path: createCDNPath('bundle.min.js'),
 gzip: true,
 limit: '27.5 KB',
 limit: '28 KB',
 },
 {
 name: 'CDN Bundle (incl. Tracing)',
 path: createCDNPath('bundle.tracing.min.js'),
 gzip: true,
 limit: '42.5 KB',
 limit: '43 KB',
 },
 {
 name: 'CDN Bundle (incl. Tracing, Replay)',
Expand DownExpand Up@@ -234,7 +234,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['next/router', 'next/constants'],
 gzip: true,
 limit: '46.5 KB',
 limit: '47 KB',
 },
 // SvelteKit SDK (ESM)
 {
Expand All@@ -243,7 +243,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['$app/stores'],
 gzip: true,
 limit: '42.5 KB',
 limit: '43 KB',
 },
 // Node-Core SDK (ESM)
 {
Expand All@@ -261,7 +261,7 @@ module.exports = [
 import: createImport('init'),
 ignore: [...builtinModules, ...nodePrefixedBuiltinModules],
 gzip: true,
 limit: '162.5 KB',
 limit: '163 KB',
 },
 {
 name: '@sentry/node - without tracing',
Expand Down

8 changes: 8 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/init.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 enhanceFetchErrorMessages: false,
});

49 changes: 49 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/subject.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
// Based on possible TypeError exceptions from https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch

// Network error (e.g. ad-blocked, offline, page does not exist, ...)
window.networkError = () => {
 fetch('http://sentry-test-external.io/does-not-exist');
};

window.networkErrorSubdomain = () => {
 fetch('http://subdomain.sentry-test-external.io/does-not-exist');
};

window.networkErrorWithPort = () => {
 fetch('http://sentry-test-external.io:3000/does-not-exist');
};

// Invalid header also produces TypeError
window.invalidHeaderName = () => {
 fetch('http://sentry-test-external.io/invalid-header-name', { headers: { 'C ontent-Type': 'text/xml' } });
};

// Invalid header value also produces TypeError
window.invalidHeaderValue = () => {
 fetch('http://sentry-test-external.io/invalid-header-value', { headers: ['Content-Type', 'text/html', 'extra'] });
};

// Invalid URL scheme
window.invalidUrlScheme = () => {
 fetch('blub://sentry-test-external.io/invalid-scheme');
};

// URL includes credentials
window.credentialsInUrl = () => {
 fetch('https://user:password@sentry-test-external.io/credentials-in-url');
};

// Invalid mode
window.invalidMode = () => {
 fetch('https://sentry-test-external.io/invalid-mode', { mode: 'navigate' });
};

// Invalid request method
window.invalidMethod = () => {
 fetch('http://sentry-test-external.io/invalid-method', { method: 'CONNECT' });
};

// No-cors mode with cors-required method
window.noCorsMethod = () => {
 fetch('http://sentry-test-external.io/no-cors-method', { mode: 'no-cors', method: 'PUT' });
};

113 changes: 113 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,113 @@
import { expect } from '@playwright/test';
import { sentryTest } from '../../../utils/fixtures';
import { envelopeRequestParser, waitForErrorRequest } from '../../../utils/helpers';

sentryTest(
 'enhanceFetchErrorMessages: false: enhances error for Sentry while preserving original',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);
 const pageErrorPromise = new Promise<string>(resolve => {
 page.on('pageerror', error => {
 resolve(error.message);
 });
 });

 await page.goto(url);
 await page.evaluate('networkError()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);
 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('sentry-test-external.io');

 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

sentryTest(
 'enhanceFetchErrorMessages: false: enhances subdomain errors',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);
 const pageErrorPromise = new Promise<string>(resolve => page.on('pageerror', error => resolve(error.message)));

 await page.goto(url);
 await page.evaluate('networkErrorSubdomain()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);

 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('subdomain.sentry-test-external.io');
 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

sentryTest(
 'enhanceFetchErrorMessages: false: includes port in hostname',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);

 const pageErrorPromise = new Promise<string>(resolve => page.on('pageerror', error => resolve(error.message)));

 await page.goto(url);
 await page.evaluate('networkErrorWithPort()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);

 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('sentry-test-external.io:3000');
 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

8 changes: 8 additions & 0 deletions
...ckages/browser-integration-tests/suites/errors/fetch-enhance-messages-report-only/init.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 enhanceFetchErrorMessages: 'report-only',
});

49 changes: 49 additions & 0 deletions
...ges/browser-integration-tests/suites/errors/fetch-enhance-messages-report-only/subject.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
// Based on possible TypeError exceptions from https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch

// Network error (e.g. ad-blocked, offline, page does not exist, ...)
window.networkError = () => {
 fetch('http://sentry-test-external.io/does-not-exist');
};

window.networkErrorSubdomain = () => {
 fetch('http://subdomain.sentry-test-external.io/does-not-exist');
};

window.networkErrorWithPort = () => {
 fetch('http://sentry-test-external.io:3000/does-not-exist');
};

// Invalid header also produces TypeError
window.invalidHeaderName = () => {
 fetch('http://sentry-test-external.io/invalid-header-name', { headers: { 'C ontent-Type': 'text/xml' } });
};

// Invalid header value also produces TypeError
window.invalidHeaderValue = () => {
 fetch('http://sentry-test-external.io/invalid-header-value', { headers: ['Content-Type', 'text/html', 'extra'] });
};

// Invalid URL scheme
window.invalidUrlScheme = () => {
 fetch('blub://sentry-test-external.io/invalid-scheme');
};

// URL includes credentials
window.credentialsInUrl = () => {
 fetch('https://user:password@sentry-test-external.io/credentials-in-url');
};

// Invalid mode
window.invalidMode = () => {
 fetch('https://sentry-test-external.io/invalid-mode', { mode: 'navigate' });
};

// Invalid request method
window.invalidMethod = () => {
 fetch('http://sentry-test-external.io/invalid-method', { method: 'CONNECT' });
};

// No-cors mode with cors-required method
window.noCorsMethod = () => {
 fetch('http://sentry-test-external.io/no-cors-method', { mode: 'no-cors', method: 'PUT' });
};
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Strip utm_, fbclid, gclid, etc. from all links on page
(function() {
var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',
'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',
'ref', 'ref_src', 'source', 'medium', 'campaign'];
function cleanUrl(url) {
try {
var u = new URL(url, window.location.origin);
var changed = false;
trackingParams.forEach(function(p) {
if (u.searchParams.has(p)) {
u.searchParams.delete(p);
changed = true;
}
});
return changed ? u.toString() : url;
} catch (e) {
return url;
}
}
function cleanLinks() {
document.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
cleanLinks();
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1) {
if (node.tagName === 'A') cleanLinks();
node.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '
feat(core): Add option to enhance the fetch error message by JPeer264 · Pull Request #18466 · getsentry/sentry-javascript · GitHub
Skip to content
feat(core): Add option to enhance the fetch error message#18466

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 Merged

JPeer264
merged 10 commits into

from

Jan 12, 2026
 Merged


feat(core): Add option to enhance the fetch error message
#18466
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aff7d32

feat(core): Add option to enhance the fetch error message


JPeer264 Dec 10, 2025
2fae839

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Dec 15, 2025
8f4e49f

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
56f4d61

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
acb01af

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
0006201

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
f0e0bc6

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
52fafca

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
1a07ef6

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Jan 9, 2026
254b83c

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Jan 12, 2026

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16 changes: 8 additions & 8 deletions
.size-limit.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -8,7 +8,7 @@ module.exports = [
 path: 'packages/browser/build/npm/esm/prod/index.js',
 import: createImport('init'),
 gzip: true,
 limit: '25 KB',
 limit: '25.5 KB',
 },
 {
 name: '@sentry/browser - with treeshaking flags',
Expand DownExpand Up@@ -148,7 +148,7 @@ module.exports = [
 import: createImport('init', 'ErrorBoundary', 'reactRouterV6BrowserTracingIntegration'),
 ignore: ['react/jsx-runtime'],
 gzip: true,
 limit: '44 KB',
 limit: '44.5 KB',
 },
 // Vue SDK (ESM)
 {
Expand All@@ -171,20 +171,20 @@ module.exports = [
 path: 'packages/svelte/build/esm/index.js',
 import: createImport('init'),
 gzip: true,
 limit: '25 KB',
 limit: '25.5 KB',
 },
 // Browser CDN bundles
 {
 name: 'CDN Bundle',
 path: createCDNPath('bundle.min.js'),
 gzip: true,
 limit: '27.5 KB',
 limit: '28 KB',
 },
 {
 name: 'CDN Bundle (incl. Tracing)',
 path: createCDNPath('bundle.tracing.min.js'),
 gzip: true,
 limit: '42.5 KB',
 limit: '43 KB',
 },
 {
 name: 'CDN Bundle (incl. Tracing, Replay)',
Expand DownExpand Up@@ -234,7 +234,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['next/router', 'next/constants'],
 gzip: true,
 limit: '46.5 KB',
 limit: '47 KB',
 },
 // SvelteKit SDK (ESM)
 {
Expand All@@ -243,7 +243,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['$app/stores'],
 gzip: true,
 limit: '42.5 KB',
 limit: '43 KB',
 },
 // Node-Core SDK (ESM)
 {
Expand All@@ -261,7 +261,7 @@ module.exports = [
 import: createImport('init'),
 ignore: [...builtinModules, ...nodePrefixedBuiltinModules],
 gzip: true,
 limit: '162.5 KB',
 limit: '163 KB',
 },
 {
 name: '@sentry/node - without tracing',
Expand Down

8 changes: 8 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/init.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 enhanceFetchErrorMessages: false,
});

49 changes: 49 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/subject.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
// Based on possible TypeError exceptions from https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch

// Network error (e.g. ad-blocked, offline, page does not exist, ...)
window.networkError = () => {
 fetch('http://sentry-test-external.io/does-not-exist');
};

window.networkErrorSubdomain = () => {
 fetch('http://subdomain.sentry-test-external.io/does-not-exist');
};

window.networkErrorWithPort = () => {
 fetch('http://sentry-test-external.io:3000/does-not-exist');
};

// Invalid header also produces TypeError
window.invalidHeaderName = () => {
 fetch('http://sentry-test-external.io/invalid-header-name', { headers: { 'C ontent-Type': 'text/xml' } });
};

// Invalid header value also produces TypeError
window.invalidHeaderValue = () => {
 fetch('http://sentry-test-external.io/invalid-header-value', { headers: ['Content-Type', 'text/html', 'extra'] });
};

// Invalid URL scheme
window.invalidUrlScheme = () => {
 fetch('blub://sentry-test-external.io/invalid-scheme');
};

// URL includes credentials
window.credentialsInUrl = () => {
 fetch('https://user:password@sentry-test-external.io/credentials-in-url');
};

// Invalid mode
window.invalidMode = () => {
 fetch('https://sentry-test-external.io/invalid-mode', { mode: 'navigate' });
};

// Invalid request method
window.invalidMethod = () => {
 fetch('http://sentry-test-external.io/invalid-method', { method: 'CONNECT' });
};

// No-cors mode with cors-required method
window.noCorsMethod = () => {
 fetch('http://sentry-test-external.io/no-cors-method', { mode: 'no-cors', method: 'PUT' });
};

113 changes: 113 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,113 @@
import { expect } from '@playwright/test';
import { sentryTest } from '../../../utils/fixtures';
import { envelopeRequestParser, waitForErrorRequest } from '../../../utils/helpers';

sentryTest(
 'enhanceFetchErrorMessages: false: enhances error for Sentry while preserving original',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);
 const pageErrorPromise = new Promise<string>(resolve => {
 page.on('pageerror', error => {
 resolve(error.message);
 });
 });

 await page.goto(url);
 await page.evaluate('networkError()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);
 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('sentry-test-external.io');

 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

sentryTest(
 'enhanceFetchErrorMessages: false: enhances subdomain errors',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);
 const pageErrorPromise = new Promise<string>(resolve => page.on('pageerror', error => resolve(error.message)));

 await page.goto(url);
 await page.evaluate('networkErrorSubdomain()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);

 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('subdomain.sentry-test-external.io');
 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

sentryTest(
 'enhanceFetchErrorMessages: false: includes port in hostname',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);

 const pageErrorPromise = new Promise<string>(resolve => page.on('pageerror', error => resolve(error.message)));

 await page.goto(url);
 await page.evaluate('networkErrorWithPort()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);

 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('sentry-test-external.io:3000');
 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

8 changes: 8 additions & 0 deletions
...ckages/browser-integration-tests/suites/errors/fetch-enhance-messages-report-only/init.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 enhanceFetchErrorMessages: 'report-only',
});

49 changes: 49 additions & 0 deletions
...ges/browser-integration-tests/suites/errors/fetch-enhance-messages-report-only/subject.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
// Based on possible TypeError exceptions from https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch

// Network error (e.g. ad-blocked, offline, page does not exist, ...)
window.networkError = () => {
 fetch('http://sentry-test-external.io/does-not-exist');
};

window.networkErrorSubdomain = () => {
 fetch('http://subdomain.sentry-test-external.io/does-not-exist');
};

window.networkErrorWithPort = () => {
 fetch('http://sentry-test-external.io:3000/does-not-exist');
};

// Invalid header also produces TypeError
window.invalidHeaderName = () => {
 fetch('http://sentry-test-external.io/invalid-header-name', { headers: { 'C ontent-Type': 'text/xml' } });
};

// Invalid header value also produces TypeError
window.invalidHeaderValue = () => {
 fetch('http://sentry-test-external.io/invalid-header-value', { headers: ['Content-Type', 'text/html', 'extra'] });
};

// Invalid URL scheme
window.invalidUrlScheme = () => {
 fetch('blub://sentry-test-external.io/invalid-scheme');
};

// URL includes credentials
window.credentialsInUrl = () => {
 fetch('https://user:password@sentry-test-external.io/credentials-in-url');
};

// Invalid mode
window.invalidMode = () => {
 fetch('https://sentry-test-external.io/invalid-mode', { mode: 'navigate' });
};

// Invalid request method
window.invalidMethod = () => {
 fetch('http://sentry-test-external.io/invalid-method', { method: 'CONNECT' });
};

// No-cors mode with cors-required method
window.noCorsMethod = () => {
 fetch('http://sentry-test-external.io/no-cors-method', { mode: 'no-cors', method: 'PUT' });
};
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Auto-enable theater mode on YouTube
(function() {
function tryTheater() {
var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]');
if (btn && !btn.classList.contains('activated')) {
btn.click();
}
}
// Try immediately
tryTheater();
// Try after navigation (SPA)
var lastUrl = location.href;
setInterval(function() {
if (location.href !== lastUrl) {
lastUrl = location.href;
setTimeout(tryTheater, 500);
}
}, 1000);
// Also try on player load
var observer = new MutationObserver(tryTheater);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
feat(core): Add option to enhance the fetch error message by JPeer264 · Pull Request #18466 · getsentry/sentry-javascript · GitHub
Skip to content
feat(core): Add option to enhance the fetch error message#18466

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

 Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Merged

JPeer264
merged 10 commits into

from

Jan 12, 2026
 Merged


feat(core): Add option to enhance the fetch error message
#18466
Show file tree
Hide file tree
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Commits

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Hold shift + click to select a range
aff7d32

feat(core): Add option to enhance the fetch error message


JPeer264 Dec 10, 2025
2fae839

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Dec 15, 2025
8f4e49f

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
56f4d61

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
acb01af

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
0006201

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
f0e0bc6

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
52fafca

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
1a07ef6

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Jan 9, 2026
254b83c

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Jan 12, 2026

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Filter by extension
Conversations

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16 changes: 8 additions & 8 deletions
.size-limit.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -8,7 +8,7 @@ module.exports = [
 path: 'packages/browser/build/npm/esm/prod/index.js',
 import: createImport('init'),
 gzip: true,
 limit: '25 KB',
 limit: '25.5 KB',
 },
 {
 name: '@sentry/browser - with treeshaking flags',
Expand DownExpand Up@@ -148,7 +148,7 @@ module.exports = [
 import: createImport('init', 'ErrorBoundary', 'reactRouterV6BrowserTracingIntegration'),
 ignore: ['react/jsx-runtime'],
 gzip: true,
 limit: '44 KB',
 limit: '44.5 KB',
 },
 // Vue SDK (ESM)
 {
Expand All@@ -171,20 +171,20 @@ module.exports = [
 path: 'packages/svelte/build/esm/index.js',
 import: createImport('init'),
 gzip: true,
 limit: '25 KB',
 limit: '25.5 KB',
 },
 // Browser CDN bundles
 {
 name: 'CDN Bundle',
 path: createCDNPath('bundle.min.js'),
 gzip: true,
 limit: '27.5 KB',
 limit: '28 KB',
 },
 {
 name: 'CDN Bundle (incl. Tracing)',
 path: createCDNPath('bundle.tracing.min.js'),
 gzip: true,
 limit: '42.5 KB',
 limit: '43 KB',
 },
 {
 name: 'CDN Bundle (incl. Tracing, Replay)',
Expand DownExpand Up@@ -234,7 +234,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['next/router', 'next/constants'],
 gzip: true,
 limit: '46.5 KB',
 limit: '47 KB',
 },
 // SvelteKit SDK (ESM)
 {
Expand All@@ -243,7 +243,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['$app/stores'],
 gzip: true,
 limit: '42.5 KB',
 limit: '43 KB',
 },
 // Node-Core SDK (ESM)
 {
Expand All@@ -261,7 +261,7 @@ module.exports = [
 import: createImport('init'),
 ignore: [...builtinModules, ...nodePrefixedBuiltinModules],
 gzip: true,
 limit: '162.5 KB',
 limit: '163 KB',
 },
 {
 name: '@sentry/node - without tracing',
Expand Down

8 changes: 8 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/init.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 enhanceFetchErrorMessages: false,
});

49 changes: 49 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/subject.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
// Based on possible TypeError exceptions from https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch

// Network error (e.g. ad-blocked, offline, page does not exist, ...)
window.networkError = () => {
 fetch('http://sentry-test-external.io/does-not-exist');
};

window.networkErrorSubdomain = () => {
 fetch('http://subdomain.sentry-test-external.io/does-not-exist');
};

window.networkErrorWithPort = () => {
 fetch('http://sentry-test-external.io:3000/does-not-exist');
};

// Invalid header also produces TypeError
window.invalidHeaderName = () => {
 fetch('http://sentry-test-external.io/invalid-header-name', { headers: { 'C ontent-Type': 'text/xml' } });
};

// Invalid header value also produces TypeError
window.invalidHeaderValue = () => {
 fetch('http://sentry-test-external.io/invalid-header-value', { headers: ['Content-Type', 'text/html', 'extra'] });
};

// Invalid URL scheme
window.invalidUrlScheme = () => {
 fetch('blub://sentry-test-external.io/invalid-scheme');
};

// URL includes credentials
window.credentialsInUrl = () => {
 fetch('https://user:password@sentry-test-external.io/credentials-in-url');
};

// Invalid mode
window.invalidMode = () => {
 fetch('https://sentry-test-external.io/invalid-mode', { mode: 'navigate' });
};

// Invalid request method
window.invalidMethod = () => {
 fetch('http://sentry-test-external.io/invalid-method', { method: 'CONNECT' });
};

// No-cors mode with cors-required method
window.noCorsMethod = () => {
 fetch('http://sentry-test-external.io/no-cors-method', { mode: 'no-cors', method: 'PUT' });
};

113 changes: 113 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,113 @@
import { expect } from '@playwright/test';
import { sentryTest } from '../../../utils/fixtures';
import { envelopeRequestParser, waitForErrorRequest } from '../../../utils/helpers';

sentryTest(
 'enhanceFetchErrorMessages: false: enhances error for Sentry while preserving original',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);
 const pageErrorPromise = new Promise<string>(resolve => {
 page.on('pageerror', error => {
 resolve(error.message);
 });
 });

 await page.goto(url);
 await page.evaluate('networkError()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);
 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('sentry-test-external.io');

 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

sentryTest(
 'enhanceFetchErrorMessages: false: enhances subdomain errors',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);
 const pageErrorPromise = new Promise<string>(resolve => page.on('pageerror', error => resolve(error.message)));

 await page.goto(url);
 await page.evaluate('networkErrorSubdomain()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);

 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('subdomain.sentry-test-external.io');
 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

sentryTest(
 'enhanceFetchErrorMessages: false: includes port in hostname',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);

 const pageErrorPromise = new Promise<string>(resolve => page.on('pageerror', error => resolve(error.message)));

 await page.goto(url);
 await page.evaluate('networkErrorWithPort()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);

 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('sentry-test-external.io:3000');
 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

8 changes: 8 additions & 0 deletions
...ckages/browser-integration-tests/suites/errors/fetch-enhance-messages-report-only/init.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 enhanceFetchErrorMessages: 'report-only',
});

49 changes: 49 additions & 0 deletions
...ges/browser-integration-tests/suites/errors/fetch-enhance-messages-report-only/subject.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
// Based on possible TypeError exceptions from https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch

// Network error (e.g. ad-blocked, offline, page does not exist, ...)
window.networkError = () => {
 fetch('http://sentry-test-external.io/does-not-exist');
};

window.networkErrorSubdomain = () => {
 fetch('http://subdomain.sentry-test-external.io/does-not-exist');
};

window.networkErrorWithPort = () => {
 fetch('http://sentry-test-external.io:3000/does-not-exist');
};

// Invalid header also produces TypeError
window.invalidHeaderName = () => {
 fetch('http://sentry-test-external.io/invalid-header-name', { headers: { 'C ontent-Type': 'text/xml' } });
};

// Invalid header value also produces TypeError
window.invalidHeaderValue = () => {
 fetch('http://sentry-test-external.io/invalid-header-value', { headers: ['Content-Type', 'text/html', 'extra'] });
};

// Invalid URL scheme
window.invalidUrlScheme = () => {
 fetch('blub://sentry-test-external.io/invalid-scheme');
};

// URL includes credentials
window.credentialsInUrl = () => {
 fetch('https://user:password@sentry-test-external.io/credentials-in-url');
};

// Invalid mode
window.invalidMode = () => {
 fetch('https://sentry-test-external.io/invalid-mode', { mode: 'navigate' });
};

// Invalid request method
window.invalidMethod = () => {
 fetch('http://sentry-test-external.io/invalid-method', { method: 'CONNECT' });
};

// No-cors mode with cors-required method
window.noCorsMethod = () => {
 fetch('http://sentry-test-external.io/no-cors-method', { mode: 'no-cors', method: 'PUT' });
};
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Remove or un-stick sticky/fixed headers that block content
(function() {
function unstick() {
document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) {
if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {
el.style.position = 'static';
el.style.top = 'auto';
el.style.zIndex = 'auto';
}
});
}
unstick();
var observer = new MutationObserver(unstick);
observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });
})();
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
feat(core): Add option to enhance the fetch error message by JPeer264 · Pull Request #18466 · getsentry/sentry-javascript · GitHub
Skip to content
feat(core): Add option to enhance the fetch error message#18466

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to your account

 Merged

JPeer264
merged 10 commits into

from

Jan 12, 2026
 Merged


feat(core): Add option to enhance the fetch error message
#18466
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aff7d32

feat(core): Add option to enhance the fetch error message


JPeer264 Dec 10, 2025
2fae839

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Dec 15, 2025
8f4e49f

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
56f4d61

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
acb01af

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
0006201

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
f0e0bc6

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
52fafca

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
1a07ef6

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Jan 9, 2026
254b83c

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Jan 12, 2026

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16 changes: 8 additions & 8 deletions
.size-limit.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -8,7 +8,7 @@ module.exports = [
 path: 'packages/browser/build/npm/esm/prod/index.js',
 import: createImport('init'),
 gzip: true,
 limit: '25 KB',
 limit: '25.5 KB',
 },
 {
 name: '@sentry/browser - with treeshaking flags',
Expand DownExpand Up@@ -148,7 +148,7 @@ module.exports = [
 import: createImport('init', 'ErrorBoundary', 'reactRouterV6BrowserTracingIntegration'),
 ignore: ['react/jsx-runtime'],
 gzip: true,
 limit: '44 KB',
 limit: '44.5 KB',
 },
 // Vue SDK (ESM)
 {
Expand All@@ -171,20 +171,20 @@ module.exports = [
 path: 'packages/svelte/build/esm/index.js',
 import: createImport('init'),
 gzip: true,
 limit: '25 KB',
 limit: '25.5 KB',
 },
 // Browser CDN bundles
 {
 name: 'CDN Bundle',
 path: createCDNPath('bundle.min.js'),
 gzip: true,
 limit: '27.5 KB',
 limit: '28 KB',
 },
 {
 name: 'CDN Bundle (incl. Tracing)',
 path: createCDNPath('bundle.tracing.min.js'),
 gzip: true,
 limit: '42.5 KB',
 limit: '43 KB',
 },
 {
 name: 'CDN Bundle (incl. Tracing, Replay)',
Expand DownExpand Up@@ -234,7 +234,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['next/router', 'next/constants'],
 gzip: true,
 limit: '46.5 KB',
 limit: '47 KB',
 },
 // SvelteKit SDK (ESM)
 {
Expand All@@ -243,7 +243,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['$app/stores'],
 gzip: true,
 limit: '42.5 KB',
 limit: '43 KB',
 },
 // Node-Core SDK (ESM)
 {
Expand All@@ -261,7 +261,7 @@ module.exports = [
 import: createImport('init'),
 ignore: [...builtinModules, ...nodePrefixedBuiltinModules],
 gzip: true,
 limit: '162.5 KB',
 limit: '163 KB',
 },
 {
 name: '@sentry/node - without tracing',
Expand Down

8 changes: 8 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/init.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 enhanceFetchErrorMessages: false,
});

49 changes: 49 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/subject.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
// Based on possible TypeError exceptions from https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch

// Network error (e.g. ad-blocked, offline, page does not exist, ...)
window.networkError = () => {
 fetch('http://sentry-test-external.io/does-not-exist');
};

window.networkErrorSubdomain = () => {
 fetch('http://subdomain.sentry-test-external.io/does-not-exist');
};

window.networkErrorWithPort = () => {
 fetch('http://sentry-test-external.io:3000/does-not-exist');
};

// Invalid header also produces TypeError
window.invalidHeaderName = () => {
 fetch('http://sentry-test-external.io/invalid-header-name', { headers: { 'C ontent-Type': 'text/xml' } });
};

// Invalid header value also produces TypeError
window.invalidHeaderValue = () => {
 fetch('http://sentry-test-external.io/invalid-header-value', { headers: ['Content-Type', 'text/html', 'extra'] });
};

// Invalid URL scheme
window.invalidUrlScheme = () => {
 fetch('blub://sentry-test-external.io/invalid-scheme');
};

// URL includes credentials
window.credentialsInUrl = () => {
 fetch('https://user:password@sentry-test-external.io/credentials-in-url');
};

// Invalid mode
window.invalidMode = () => {
 fetch('https://sentry-test-external.io/invalid-mode', { mode: 'navigate' });
};

// Invalid request method
window.invalidMethod = () => {
 fetch('http://sentry-test-external.io/invalid-method', { method: 'CONNECT' });
};

// No-cors mode with cors-required method
window.noCorsMethod = () => {
 fetch('http://sentry-test-external.io/no-cors-method', { mode: 'no-cors', method: 'PUT' });
};

113 changes: 113 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/test.ts

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,113 @@
import { expect } from '@playwright/test';
import { sentryTest } from '../../../utils/fixtures';
import { envelopeRequestParser, waitForErrorRequest } from '../../../utils/helpers';

sentryTest(
 'enhanceFetchErrorMessages: false: enhances error for Sentry while preserving original',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);
 const pageErrorPromise = new Promise<string>(resolve => {
 page.on('pageerror', error => {
 resolve(error.message);
 });
 });

 await page.goto(url);
 await page.evaluate('networkError()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);
 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('sentry-test-external.io');

 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

sentryTest(
 'enhanceFetchErrorMessages: false: enhances subdomain errors',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);
 const pageErrorPromise = new Promise<string>(resolve => page.on('pageerror', error => resolve(error.message)));

 await page.goto(url);
 await page.evaluate('networkErrorSubdomain()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);

 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('subdomain.sentry-test-external.io');
 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

sentryTest(
 'enhanceFetchErrorMessages: false: includes port in hostname',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);

 const pageErrorPromise = new Promise<string>(resolve => page.on('pageerror', error => resolve(error.message)));

 await page.goto(url);
 await page.evaluate('networkErrorWithPort()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);

 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('sentry-test-external.io:3000');
 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

8 changes: 8 additions & 0 deletions
...ckages/browser-integration-tests/suites/errors/fetch-enhance-messages-report-only/init.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 enhanceFetchErrorMessages: 'report-only',
});

49 changes: 49 additions & 0 deletions
...ges/browser-integration-tests/suites/errors/fetch-enhance-messages-report-only/subject.js

View file


Open in desktop

Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
// Based on possible TypeError exceptions from https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch

// Network error (e.g. ad-blocked, offline, page does not exist, ...)
window.networkError = () => {
 fetch('http://sentry-test-external.io/does-not-exist');
};

window.networkErrorSubdomain = () => {
 fetch('http://subdomain.sentry-test-external.io/does-not-exist');
};

window.networkErrorWithPort = () => {
 fetch('http://sentry-test-external.io:3000/does-not-exist');
};

// Invalid header also produces TypeError
window.invalidHeaderName = () => {
 fetch('http://sentry-test-external.io/invalid-header-name', { headers: { 'C ontent-Type': 'text/xml' } });
};

// Invalid header value also produces TypeError
window.invalidHeaderValue = () => {
 fetch('http://sentry-test-external.io/invalid-header-value', { headers: ['Content-Type', 'text/html', 'extra'] });
};

// Invalid URL scheme
window.invalidUrlScheme = () => {
 fetch('blub://sentry-test-external.io/invalid-scheme');
};

// URL includes credentials
window.credentialsInUrl = () => {
 fetch('https://user:password@sentry-test-external.io/credentials-in-url');
};

// Invalid mode
window.invalidMode = () => {
 fetch('https://sentry-test-external.io/invalid-mode', { mode: 'navigate' });
};

// Invalid request method
window.invalidMethod = () => {
 fetch('http://sentry-test-external.io/invalid-method', { method: 'CONNECT' });
};

// No-cors mode with cors-required method
window.noCorsMethod = () => {
 fetch('http://sentry-test-external.io/no-cors-method', { mode: 'no-cors', method: 'PUT' });
};
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Universal Dark Mode - works on any site
(function() {
var enabled = true;
function applyDarkMode() {
if (!enabled) return;
// Create style element if it doesn't exist
var style = document.getElementById('universal-dark-mode-style');
if (!style) {
style = document.createElement('style');
style.id = 'universal-dark-mode-style';
document.head.appendChild(style);
}
// Dark mode CSS - inverts colors but preserves images/video
style.textContent = '
/* Invert everything except media */
html {
filter: invert(1) hue-rotate(180deg) !important;
background: #1a1a2e !important;
}
/* Restore images, videos, iframes, canvas */
img, video, iframe, canvas, svg, picture, [style*="background-image"] {
filter: invert(1) hue-rotate(180deg) !important;
}
/* Preserve specific elements that should not be inverted */
.no-dark-mode, .no-dark-mode *,
[data-theme="light"], [data-theme="light"],
.ace_editor, .ace_editor *,
.CodeMirror, .CodeMirror *,
.monaco-editor, .monaco-editor *,
.markdown-body pre, .markdown-body pre *,
.highlight, .highlight *,
pre code, pre code * {
filter: none !important;
}
/* Fix common UI elements */
.modal, .popup, .dropdown-menu, .tooltip, .popover {
filter: invert(1) hue-rotate(180deg) !important;
background: #2d2d44 !important;
border-color: #444 !important;
}
/* Scrollbars */
::-webkit-scrollbar { background: #1a1a2e !important; }
::-webkit-scrollbar-thumb { background: #444 !important; }
::-webkit-scrollbar-thumb:hover { background: #555 !important; }
/* Selection */
::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
';
}
function removeDarkMode() {
var style = document.getElementById('universal-dark-mode-style');
if (style) style.remove();
}
// Toggle with Alt+Shift+D
document.addEventListener('keydown', function(e) {
if (e.altKey && e.shiftKey && e.key === 'D') {
e.preventDefault();
enabled = !enabled;
if (enabled) {
applyDarkMode();
console.log('[Universal Dark Mode] Enabled');
} else {
removeDarkMode();
console.log('[Universal Dark Mode] Disabled');
}
}
});
// Apply on load
applyDarkMode();
// Re-apply on dynamic content
var observer = new MutationObserver(function(mutations) {
if (enabled && !document.getElementById('universal-dark-mode-style')) {
applyDarkMode();
}
});
observer.observe(document.head, { childList: true });
console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');
})();
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();
feat(core): Add option to enhance the fetch error message by JPeer264 · Pull Request #18466 · getsentry/sentry-javascript · GitHub
Skip to content
feat(core): Add option to enhance the fetch error message#18466

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

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By clicking “Sign up for GitHub”, you agree to our terms of service and
privacy statement. We’ll occasionally send you account related emails.

Already on GitHub?
Sign in
to your account

 Merged

JPeer264
merged 10 commits into

from

Jan 12, 2026
 Merged


feat(core): Add option to enhance the fetch error message
#18466
Show file tree
Hide file tree
 Changes from all commits
Commits

Show all changes


10 commits


Select commit
Hold shift + click to select a range
aff7d32

feat(core): Add option to enhance the fetch error message


JPeer264 Dec 10, 2025
2fae839

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Dec 15, 2025
8f4e49f

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
56f4d61

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
acb01af

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
0006201

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
f0e0bc6

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
52fafca

Update dev-packages/browser-integration-tests/suites/errors/fetch-enh…


JPeer264 Dec 18, 2025
1a07ef6

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Jan 9, 2026
254b83c

fixup! feat(core): Add option to enhance the fetch error message


JPeer264 Jan 12, 2026

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16 changes: 8 additions & 8 deletions
.size-limit.js

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Original file line numberDiff line numberDiff line change
Expand Up@@ -8,7 +8,7 @@ module.exports = [
 path: 'packages/browser/build/npm/esm/prod/index.js',
 import: createImport('init'),
 gzip: true,
 limit: '25 KB',
 limit: '25.5 KB',
 },
 {
 name: '@sentry/browser - with treeshaking flags',
Expand DownExpand Up@@ -148,7 +148,7 @@ module.exports = [
 import: createImport('init', 'ErrorBoundary', 'reactRouterV6BrowserTracingIntegration'),
 ignore: ['react/jsx-runtime'],
 gzip: true,
 limit: '44 KB',
 limit: '44.5 KB',
 },
 // Vue SDK (ESM)
 {
Expand All@@ -171,20 +171,20 @@ module.exports = [
 path: 'packages/svelte/build/esm/index.js',
 import: createImport('init'),
 gzip: true,
 limit: '25 KB',
 limit: '25.5 KB',
 },
 // Browser CDN bundles
 {
 name: 'CDN Bundle',
 path: createCDNPath('bundle.min.js'),
 gzip: true,
 limit: '27.5 KB',
 limit: '28 KB',
 },
 {
 name: 'CDN Bundle (incl. Tracing)',
 path: createCDNPath('bundle.tracing.min.js'),
 gzip: true,
 limit: '42.5 KB',
 limit: '43 KB',
 },
 {
 name: 'CDN Bundle (incl. Tracing, Replay)',
Expand DownExpand Up@@ -234,7 +234,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['next/router', 'next/constants'],
 gzip: true,
 limit: '46.5 KB',
 limit: '47 KB',
 },
 // SvelteKit SDK (ESM)
 {
Expand All@@ -243,7 +243,7 @@ module.exports = [
 import: createImport('init'),
 ignore: ['$app/stores'],
 gzip: true,
 limit: '42.5 KB',
 limit: '43 KB',
 },
 // Node-Core SDK (ESM)
 {
Expand All@@ -261,7 +261,7 @@ module.exports = [
 import: createImport('init'),
 ignore: [...builtinModules, ...nodePrefixedBuiltinModules],
 gzip: true,
 limit: '162.5 KB',
 limit: '163 KB',
 },
 {
 name: '@sentry/node - without tracing',
Expand Down

8 changes: 8 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/init.js

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 enhanceFetchErrorMessages: false,
});

49 changes: 49 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/subject.js

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
// Based on possible TypeError exceptions from https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch

// Network error (e.g. ad-blocked, offline, page does not exist, ...)
window.networkError = () => {
 fetch('http://sentry-test-external.io/does-not-exist');
};

window.networkErrorSubdomain = () => {
 fetch('http://subdomain.sentry-test-external.io/does-not-exist');
};

window.networkErrorWithPort = () => {
 fetch('http://sentry-test-external.io:3000/does-not-exist');
};

// Invalid header also produces TypeError
window.invalidHeaderName = () => {
 fetch('http://sentry-test-external.io/invalid-header-name', { headers: { 'C ontent-Type': 'text/xml' } });
};

// Invalid header value also produces TypeError
window.invalidHeaderValue = () => {
 fetch('http://sentry-test-external.io/invalid-header-value', { headers: ['Content-Type', 'text/html', 'extra'] });
};

// Invalid URL scheme
window.invalidUrlScheme = () => {
 fetch('blub://sentry-test-external.io/invalid-scheme');
};

// URL includes credentials
window.credentialsInUrl = () => {
 fetch('https://user:password@sentry-test-external.io/credentials-in-url');
};

// Invalid mode
window.invalidMode = () => {
 fetch('https://sentry-test-external.io/invalid-mode', { mode: 'navigate' });
};

// Invalid request method
window.invalidMethod = () => {
 fetch('http://sentry-test-external.io/invalid-method', { method: 'CONNECT' });
};

// No-cors mode with cors-required method
window.noCorsMethod = () => {
 fetch('http://sentry-test-external.io/no-cors-method', { mode: 'no-cors', method: 'PUT' });
};

113 changes: 113 additions & 0 deletions
dev-packages/browser-integration-tests/suites/errors/fetch-enhance-messages-off/test.ts

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,113 @@
import { expect } from '@playwright/test';
import { sentryTest } from '../../../utils/fixtures';
import { envelopeRequestParser, waitForErrorRequest } from '../../../utils/helpers';

sentryTest(
 'enhanceFetchErrorMessages: false: enhances error for Sentry while preserving original',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);
 const pageErrorPromise = new Promise<string>(resolve => {
 page.on('pageerror', error => {
 resolve(error.message);
 });
 });

 await page.goto(url);
 await page.evaluate('networkError()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);
 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('sentry-test-external.io');

 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

sentryTest(
 'enhanceFetchErrorMessages: false: enhances subdomain errors',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);
 const pageErrorPromise = new Promise<string>(resolve => page.on('pageerror', error => resolve(error.message)));

 await page.goto(url);
 await page.evaluate('networkErrorSubdomain()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);

 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('subdomain.sentry-test-external.io');
 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

sentryTest(
 'enhanceFetchErrorMessages: false: includes port in hostname',
 async ({ getLocalTestUrl, page, browserName }) => {
 const url = await getLocalTestUrl({ testDir: __dirname });
 const reqPromise = waitForErrorRequest(page);

 const pageErrorPromise = new Promise<string>(resolve => page.on('pageerror', error => resolve(error.message)));

 await page.goto(url);
 await page.evaluate('networkErrorWithPort()');

 const [req, pageErrorMessage] = await Promise.all([reqPromise, pageErrorPromise]);
 const eventData = envelopeRequestParser(req);

 const originalErrorMap: Record<string, string> = {
 chromium: 'Failed to fetch',
 webkit: 'Load failed',
 firefox: 'NetworkError when attempting to fetch resource.',
 };

 const originalError = originalErrorMap[browserName];

 expect(pageErrorMessage).toContain(originalError);
 expect(pageErrorMessage).not.toContain('sentry-test-external.io:3000');
 expect(eventData.exception?.values).toHaveLength(1);
 expect(eventData.exception?.values?.[0]).toMatchObject({
 type: 'TypeError',
 value: originalError,
 mechanism: {
 handled: false,
 type: 'auto.browser.global_handlers.onunhandledrejection',
 },
 });
 },
);

8 changes: 8 additions & 0 deletions
...ckages/browser-integration-tests/suites/errors/fetch-enhance-messages-report-only/init.js

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,8 @@
import * as Sentry from '@sentry/browser';

window.Sentry = Sentry;

Sentry.init({
 dsn: 'https://public@dsn.ingest.sentry.io/1337',
 enhanceFetchErrorMessages: 'report-only',
});

49 changes: 49 additions & 0 deletions
...ges/browser-integration-tests/suites/errors/fetch-enhance-messages-report-only/subject.js

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,49 @@
// Based on possible TypeError exceptions from https://developer.mozilla.org/en-US/docs/Web/API/Window/fetch

// Network error (e.g. ad-blocked, offline, page does not exist, ...)
window.networkError = () => {
 fetch('http://sentry-test-external.io/does-not-exist');
};

window.networkErrorSubdomain = () => {
 fetch('http://subdomain.sentry-test-external.io/does-not-exist');
};

window.networkErrorWithPort = () => {
 fetch('http://sentry-test-external.io:3000/does-not-exist');
};

// Invalid header also produces TypeError
window.invalidHeaderName = () => {
 fetch('http://sentry-test-external.io/invalid-header-name', { headers: { 'C ontent-Type': 'text/xml' } });
};

// Invalid header value also produces TypeError
window.invalidHeaderValue = () => {
 fetch('http://sentry-test-external.io/invalid-header-value', { headers: ['Content-Type', 'text/html', 'extra'] });
};

// Invalid URL scheme
window.invalidUrlScheme = () => {
 fetch('blub://sentry-test-external.io/invalid-scheme');
};

// URL includes credentials
window.credentialsInUrl = () => {
 fetch('https://user:password@sentry-test-external.io/credentials-in-url');
};

// Invalid mode
window.invalidMode = () => {
 fetch('https://sentry-test-external.io/invalid-mode', { mode: 'navigate' });
};

// Invalid request method
window.invalidMethod = () => {
 fetch('http://sentry-test-external.io/invalid-method', { method: 'CONNECT' });
};

// No-cors mode with cors-required method
window.noCorsMethod = () => {
 fetch('http://sentry-test-external.io/no-cors-method', { mode: 'no-cors', method: 'PUT' });
};
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