JSDoc present in mapped types is not output in generated type literals in declaration files #62309

Open
Open
JSDoc present in mapped types is not output in generated type literals in declaration files#62309
Labels
Domain: Declaration EmitThe issue relates to the emission of d.ts filesHelp WantedYou can do thisPossible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some cases
Milestone
Backlog

Description

@jedwards1211
Andy Edwards (jedwards1211)
opened on Aug 20, 2025

🔎 Search Terms

generated declaration files mapped types jsdoc missing

🕗 Version & Regression Information

  • This is the behavior in every version I tried, and I reviewed the FAQ for entries about: I don't believe the FAQ contains anything applicable to this.

⏯ Playground Link

https://www.typescriptlang.org/play/?#code/JYWwDg9gTgLgBALzgMyhEcDkCIBNMBQBApgB6SxwDGEAdgM7z1UAWxIAhnALyIB0EAEYArYlRgAKAN4E4cAPQAqRbLmK4AZXTE4tYFR0ApDQBEIVVXEXzVyCBABc-RlGC0A5hICUAGgIBfLyIaBnhSHjhmNk4+MA4oemJpO0csDkxAvhTLOVy8-ILCuXl5OAA9CrgWCAA3YlcPFHtI6oB3ejgYNjhjMwsgA

💻 Code

This is not the same issue as #50715, that issue is about type mappings that lose the JSDoc period.

I'm talking about what happens in the .d.ts file generated for source like this where JSDoc does survive type mapping:

importzfrom'zod'exportconstschema=z.object({/** * Some nice JSDoc */foo: z.string(),})constx=schema.parse({foo: 'a'}).foo// ^^^ hovering foo shows the JSDoc

🙁 Actual behavior

Hovering the parsed .foo in the source file displays the JSDoc for the property:
Image

But if I consume the same type from the generated .d.ts file, I don't get the JSDoc:

Image

🙂 Expected behavior

We should get the same JSDoc when consuming the .d.ts file as we do when consuming the source file it was generated from.

Additional information about the issue

If we look at the generated .d.ts the problem is clear: tsc isn't outputting JSDoc it has in memory for mapped type properties to the generated type literals:

importzfrom'zod';exportdeclareconstschema: z.ZodObject<{/** * Some nice JSDoc */foo: z.ZodString;},"strip",z.ZodTypeAny,{foo: string;// (tsc should have copied the JSDoc to this property)},{foo: string;// (and to this one)}>;//# sourceMappingURL=Schema.d.ts.map

It would at least be nice to have an option to output these copies of JSDoc, even though it would make the declaration file bigger.

Activity

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    Domain: Declaration EmitThe issue relates to the emission of d.ts filesHelp WantedYou can do thisPossible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some cases

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      , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
       blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n 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;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

      Skip to content
      JSDoc present in mapped types is not output in generated type literals in declaration files #62309
      Open
      Open
      JSDoc present in mapped types is not output in generated type literals in declaration files#62309
      Labels
      Domain: Declaration EmitThe issue relates to the emission of d.ts filesHelp WantedYou can do thisPossible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some cases
      Milestone
      Backlog
      Description
      @jedwards1211
      Andy Edwards (jedwards1211)
      opened on Aug 20, 2025
      🔎 Search Terms
      generated declaration files mapped types jsdoc missing
      🕗 Version & Regression Information
      • This is the behavior in every version I tried, and I reviewed the FAQ for entries about: I don't believe the FAQ contains anything applicable to this.
      ⏯ Playground Link
      https://www.typescriptlang.org/play/?#code/JYWwDg9gTgLgBALzgMyhEcDkCIBNMBQBApgB6SxwDGEAdgM7z1UAWxIAhnALyIB0EAEYArYlRgAKAN4E4cAPQAqRbLmK4AZXTE4tYFR0ApDQBEIVVXEXzVyCBABc-RlGC0A5hICUAGgIBfLyIaBnhSHjhmNk4+MA4oemJpO0csDkxAvhTLOVy8-ILCuXl5OAA9CrgWCAA3YlcPFHtI6oB3ejgYNjhjMwsgA
      💻 Code
      This is not the same issue as #50715, that issue is about type mappings that lose the JSDoc period.
      I'm talking about what happens in the .d.ts file generated for source like this where JSDoc does survive type mapping:
      importzfrom'zod'exportconstschema=z.object({/** * Some nice JSDoc */foo: z.string(),})constx=schema.parse({foo: 'a'}).foo// ^^^ hovering foo shows the JSDoc
      🙁 Actual behavior
      Hovering the parsed .foo in the source file displays the JSDoc for the property:
      Image
      But if I consume the same type from the generated .d.ts file, I don't get the JSDoc:
      Image
      🙂 Expected behavior
      We should get the same JSDoc when consuming the .d.ts file as we do when consuming the source file it was generated from.
      Additional information about the issue
      If we look at the generated .d.ts the problem is clear: tsc isn't outputting JSDoc it has in memory for mapped type properties to the generated type literals:
      importzfrom'zod';exportdeclareconstschema: z.ZodObject<{/** * Some nice JSDoc */foo: z.ZodString;},"strip",z.ZodTypeAny,{foo: string;// (tsc should have copied the JSDoc to this property)},{foo: string;// (and to this one)}>;//# sourceMappingURL=Schema.d.ts.map
      It would at least be nice to have an option to output these copies of JSDoc, even though it would make the declaration file bigger.
      Activity
      Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
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        Labels
        Domain: Declaration EmitThe issue relates to the emission of d.ts filesHelp WantedYou can do thisPossible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some cases
        Type
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

          Skip to content
          JSDoc present in mapped types is not output in generated type literals in declaration files #62309
          Open
          Open
          JSDoc present in mapped types is not output in generated type literals in declaration files#62309
          Labels
          Domain: Declaration EmitThe issue relates to the emission of d.ts filesHelp WantedYou can do thisPossible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some cases
          Milestone
          Backlog
          Description
          @jedwards1211
          Andy Edwards (jedwards1211)
          opened on Aug 20, 2025
          🔎 Search Terms
          generated declaration files mapped types jsdoc missing
          🕗 Version & Regression Information
          • This is the behavior in every version I tried, and I reviewed the FAQ for entries about: I don't believe the FAQ contains anything applicable to this.
          ⏯ Playground Link
          https://www.typescriptlang.org/play/?#code/JYWwDg9gTgLgBALzgMyhEcDkCIBNMBQBApgB6SxwDGEAdgM7z1UAWxIAhnALyIB0EAEYArYlRgAKAN4E4cAPQAqRbLmK4AZXTE4tYFR0ApDQBEIVVXEXzVyCBABc-RlGC0A5hICUAGgIBfLyIaBnhSHjhmNk4+MA4oemJpO0csDkxAvhTLOVy8-ILCuXl5OAA9CrgWCAA3YlcPFHtI6oB3ejgYNjhjMwsgA
          💻 Code
          This is not the same issue as #50715, that issue is about type mappings that lose the JSDoc period.
          I'm talking about what happens in the .d.ts file generated for source like this where JSDoc does survive type mapping:
          importzfrom'zod'exportconstschema=z.object({/** * Some nice JSDoc */foo: z.string(),})constx=schema.parse({foo: 'a'}).foo// ^^^ hovering foo shows the JSDoc
          🙁 Actual behavior
          Hovering the parsed .foo in the source file displays the JSDoc for the property:
          Image
          But if I consume the same type from the generated .d.ts file, I don't get the JSDoc:
          Image
          🙂 Expected behavior
          We should get the same JSDoc when consuming the .d.ts file as we do when consuming the source file it was generated from.
          Additional information about the issue
          If we look at the generated .d.ts the problem is clear: tsc isn't outputting JSDoc it has in memory for mapped type properties to the generated type literals:
          importzfrom'zod';exportdeclareconstschema: z.ZodObject<{/** * Some nice JSDoc */foo: z.ZodString;},"strip",z.ZodTypeAny,{foo: string;// (tsc should have copied the JSDoc to this property)},{foo: string;// (and to this one)}>;//# sourceMappingURL=Schema.d.ts.map
          It would at least be nice to have an option to output these copies of JSDoc, even though it would make the declaration file bigger.
          Activity
          Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
          Metadata
          Metadata
          Assignees
          No one assigned
            Labels
            Domain: Declaration EmitThe issue relates to the emission of d.ts filesHelp WantedYou can do thisPossible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some cases
            Type
            No type
            Projects
            No projects
              Milestone
              Relationships
              None yet
              Development
              No branches or pull requests
              Issue actions
              
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

              Skip to content
              JSDoc present in mapped types is not output in generated type literals in declaration files #62309
              Open
              Open
              JSDoc present in mapped types is not output in generated type literals in declaration files#62309
              Labels
              Domain: Declaration EmitThe issue relates to the emission of d.ts filesHelp WantedYou can do thisPossible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some cases
              Milestone
              Backlog
              Description
              @jedwards1211
              Andy Edwards (jedwards1211)
              opened on Aug 20, 2025
              🔎 Search Terms
              generated declaration files mapped types jsdoc missing
              🕗 Version & Regression Information
              • This is the behavior in every version I tried, and I reviewed the FAQ for entries about: I don't believe the FAQ contains anything applicable to this.
              ⏯ Playground Link
              https://www.typescriptlang.org/play/?#code/JYWwDg9gTgLgBALzgMyhEcDkCIBNMBQBApgB6SxwDGEAdgM7z1UAWxIAhnALyIB0EAEYArYlRgAKAN4E4cAPQAqRbLmK4AZXTE4tYFR0ApDQBEIVVXEXzVyCBABc-RlGC0A5hICUAGgIBfLyIaBnhSHjhmNk4+MA4oemJpO0csDkxAvhTLOVy8-ILCuXl5OAA9CrgWCAA3YlcPFHtI6oB3ejgYNjhjMwsgA
              💻 Code
              This is not the same issue as #50715, that issue is about type mappings that lose the JSDoc period.
              I'm talking about what happens in the .d.ts file generated for source like this where JSDoc does survive type mapping:
              importzfrom'zod'exportconstschema=z.object({/** * Some nice JSDoc */foo: z.string(),})constx=schema.parse({foo: 'a'}).foo// ^^^ hovering foo shows the JSDoc
              🙁 Actual behavior
              Hovering the parsed .foo in the source file displays the JSDoc for the property:
              Image
              But if I consume the same type from the generated .d.ts file, I don't get the JSDoc:
              Image
              🙂 Expected behavior
              We should get the same JSDoc when consuming the .d.ts file as we do when consuming the source file it was generated from.
              Additional information about the issue
              If we look at the generated .d.ts the problem is clear: tsc isn't outputting JSDoc it has in memory for mapped type properties to the generated type literals:
              importzfrom'zod';exportdeclareconstschema: z.ZodObject<{/** * Some nice JSDoc */foo: z.ZodString;},"strip",z.ZodTypeAny,{foo: string;// (tsc should have copied the JSDoc to this property)},{foo: string;// (and to this one)}>;//# sourceMappingURL=Schema.d.ts.map
              It would at least be nice to have an option to output these copies of JSDoc, even though it would make the declaration file bigger.
              Activity
              Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
              Metadata
              Metadata
              Assignees
              No one assigned
                Labels
                Domain: Declaration EmitThe issue relates to the emission of d.ts filesHelp WantedYou can do thisPossible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some cases
                Type
                No type
                Projects
                No projects
                  Milestone
                  Relationships
                  None yet
                  Development
                  No branches or pull requests
                  Issue actions
                  
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

                  Skip to content
                  JSDoc present in mapped types is not output in generated type literals in declaration files #62309
                  Open
                  Open
                  JSDoc present in mapped types is not output in generated type literals in declaration files#62309
                  Labels
                  Domain: Declaration EmitThe issue relates to the emission of d.ts filesHelp WantedYou can do thisPossible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some cases
                  Milestone
                  Backlog
                  Description
                  @jedwards1211
                  Andy Edwards (jedwards1211)
                  opened on Aug 20, 2025
                  🔎 Search Terms
                  generated declaration files mapped types jsdoc missing
                  🕗 Version & Regression Information
                  • This is the behavior in every version I tried, and I reviewed the FAQ for entries about: I don't believe the FAQ contains anything applicable to this.
                  ⏯ Playground Link
                  https://www.typescriptlang.org/play/?#code/JYWwDg9gTgLgBALzgMyhEcDkCIBNMBQBApgB6SxwDGEAdgM7z1UAWxIAhnALyIB0EAEYArYlRgAKAN4E4cAPQAqRbLmK4AZXTE4tYFR0ApDQBEIVVXEXzVyCBABc-RlGC0A5hICUAGgIBfLyIaBnhSHjhmNk4+MA4oemJpO0csDkxAvhTLOVy8-ILCuXl5OAA9CrgWCAA3YlcPFHtI6oB3ejgYNjhjMwsgA
                  💻 Code
                  This is not the same issue as #50715, that issue is about type mappings that lose the JSDoc period.
                  I'm talking about what happens in the .d.ts file generated for source like this where JSDoc does survive type mapping:
                  importzfrom'zod'exportconstschema=z.object({/** * Some nice JSDoc */foo: z.string(),})constx=schema.parse({foo: 'a'}).foo// ^^^ hovering foo shows the JSDoc
                  🙁 Actual behavior
                  Hovering the parsed .foo in the source file displays the JSDoc for the property:
                  Image
                  But if I consume the same type from the generated .d.ts file, I don't get the JSDoc:
                  Image
                  🙂 Expected behavior
                  We should get the same JSDoc when consuming the .d.ts file as we do when consuming the source file it was generated from.
                  Additional information about the issue
                  If we look at the generated .d.ts the problem is clear: tsc isn't outputting JSDoc it has in memory for mapped type properties to the generated type literals:
                  importzfrom'zod';exportdeclareconstschema: z.ZodObject<{/** * Some nice JSDoc */foo: z.ZodString;},"strip",z.ZodTypeAny,{foo: string;// (tsc should have copied the JSDoc to this property)},{foo: string;// (and to this one)}>;//# sourceMappingURL=Schema.d.ts.map
                  It would at least be nice to have an option to output these copies of JSDoc, even though it would make the declaration file bigger.
                  Activity
                  Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
                  Metadata
                  Metadata
                  Assignees
                  No one assigned
                    Labels
                    Domain: Declaration EmitThe issue relates to the emission of d.ts filesHelp WantedYou can do thisPossible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some cases
                    Type
                    No type
                    Projects
                    No projects
                      Milestone
                      Relationships
                      None yet
                      Development
                      No branches or pull requests
                      Issue actions
                      
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

                      Skip to content
                      JSDoc present in mapped types is not output in generated type literals in declaration files #62309
                      Open
                      Open
                      JSDoc present in mapped types is not output in generated type literals in declaration files#62309
                      Labels
                      Domain: Declaration EmitThe issue relates to the emission of d.ts filesHelp WantedYou can do thisPossible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some cases
                      Milestone
                      Backlog
                      Description
                      @jedwards1211
                      Andy Edwards (jedwards1211)
                      opened on Aug 20, 2025
                      🔎 Search Terms
                      generated declaration files mapped types jsdoc missing
                      🕗 Version & Regression Information
                      • This is the behavior in every version I tried, and I reviewed the FAQ for entries about: I don't believe the FAQ contains anything applicable to this.
                      ⏯ Playground Link
                      https://www.typescriptlang.org/play/?#code/JYWwDg9gTgLgBALzgMyhEcDkCIBNMBQBApgB6SxwDGEAdgM7z1UAWxIAhnALyIB0EAEYArYlRgAKAN4E4cAPQAqRbLmK4AZXTE4tYFR0ApDQBEIVVXEXzVyCBABc-RlGC0A5hICUAGgIBfLyIaBnhSHjhmNk4+MA4oemJpO0csDkxAvhTLOVy8-ILCuXl5OAA9CrgWCAA3YlcPFHtI6oB3ejgYNjhjMwsgA
                      💻 Code
                      This is not the same issue as #50715, that issue is about type mappings that lose the JSDoc period.
                      I'm talking about what happens in the .d.ts file generated for source like this where JSDoc does survive type mapping:
                      importzfrom'zod'exportconstschema=z.object({/** * Some nice JSDoc */foo: z.string(),})constx=schema.parse({foo: 'a'}).foo// ^^^ hovering foo shows the JSDoc
                      🙁 Actual behavior
                      Hovering the parsed .foo in the source file displays the JSDoc for the property:
                      Image
                      But if I consume the same type from the generated .d.ts file, I don't get the JSDoc:
                      Image
                      🙂 Expected behavior
                      We should get the same JSDoc when consuming the .d.ts file as we do when consuming the source file it was generated from.
                      Additional information about the issue
                      If we look at the generated .d.ts the problem is clear: tsc isn't outputting JSDoc it has in memory for mapped type properties to the generated type literals:
                      importzfrom'zod';exportdeclareconstschema: z.ZodObject<{/** * Some nice JSDoc */foo: z.ZodString;},"strip",z.ZodTypeAny,{foo: string;// (tsc should have copied the JSDoc to this property)},{foo: string;// (and to this one)}>;//# sourceMappingURL=Schema.d.ts.map
                      It would at least be nice to have an option to output these copies of JSDoc, even though it would make the declaration file bigger.
                      Activity
                      Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
                      Metadata
                      Metadata
                      Assignees
                      No one assigned
                        Labels
                        Domain: Declaration EmitThe issue relates to the emission of d.ts filesHelp WantedYou can do thisPossible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some cases
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

                          Skip to content
                          JSDoc present in mapped types is not output in generated type literals in declaration files #62309
                          Open
                          Open
                          JSDoc present in mapped types is not output in generated type literals in declaration files#62309
                          Labels
                          Domain: Declaration EmitThe issue relates to the emission of d.ts filesHelp WantedYou can do thisPossible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some cases
                          Milestone
                          Backlog
                          Description
                          @jedwards1211
                          Andy Edwards (jedwards1211)
                          opened on Aug 20, 2025
                          🔎 Search Terms
                          generated declaration files mapped types jsdoc missing
                          🕗 Version & Regression Information
                          • This is the behavior in every version I tried, and I reviewed the FAQ for entries about: I don't believe the FAQ contains anything applicable to this.
                          ⏯ Playground Link
                          https://www.typescriptlang.org/play/?#code/JYWwDg9gTgLgBALzgMyhEcDkCIBNMBQBApgB6SxwDGEAdgM7z1UAWxIAhnALyIB0EAEYArYlRgAKAN4E4cAPQAqRbLmK4AZXTE4tYFR0ApDQBEIVVXEXzVyCBABc-RlGC0A5hICUAGgIBfLyIaBnhSHjhmNk4+MA4oemJpO0csDkxAvhTLOVy8-ILCuXl5OAA9CrgWCAA3YlcPFHtI6oB3ejgYNjhjMwsgA
                          💻 Code
                          This is not the same issue as #50715, that issue is about type mappings that lose the JSDoc period.
                          I'm talking about what happens in the .d.ts file generated for source like this where JSDoc does survive type mapping:
                          importzfrom'zod'exportconstschema=z.object({/** * Some nice JSDoc */foo: z.string(),})constx=schema.parse({foo: 'a'}).foo// ^^^ hovering foo shows the JSDoc
                          🙁 Actual behavior
                          Hovering the parsed .foo in the source file displays the JSDoc for the property:
                          Image
                          But if I consume the same type from the generated .d.ts file, I don't get the JSDoc:
                          Image
                          🙂 Expected behavior
                          We should get the same JSDoc when consuming the .d.ts file as we do when consuming the source file it was generated from.
                          Additional information about the issue
                          If we look at the generated .d.ts the problem is clear: tsc isn't outputting JSDoc it has in memory for mapped type properties to the generated type literals:
                          importzfrom'zod';exportdeclareconstschema: z.ZodObject<{/** * Some nice JSDoc */foo: z.ZodString;},"strip",z.ZodTypeAny,{foo: string;// (tsc should have copied the JSDoc to this property)},{foo: string;// (and to this one)}>;//# sourceMappingURL=Schema.d.ts.map
                          It would at least be nice to have an option to output these copies of JSDoc, even though it would make the declaration file bigger.
                          Activity
                          Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
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                            Labels
                            Domain: Declaration EmitThe issue relates to the emission of d.ts filesHelp WantedYou can do thisPossible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some cases
                            Type
                            No type
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                            No projects
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                              None yet
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                              No branches or pull requests
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

                              Skip to content
                              JSDoc present in mapped types is not output in generated type literals in declaration files #62309
                              Open
                              Open
                              JSDoc present in mapped types is not output in generated type literals in declaration files#62309
                              Labels
                              Domain: Declaration EmitThe issue relates to the emission of d.ts filesHelp WantedYou can do thisPossible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some cases
                              Milestone
                              Backlog
                              Description
                              @jedwards1211
                              Andy Edwards (jedwards1211)
                              opened on Aug 20, 2025
                              🔎 Search Terms
                              generated declaration files mapped types jsdoc missing
                              🕗 Version & Regression Information
                              • This is the behavior in every version I tried, and I reviewed the FAQ for entries about: I don't believe the FAQ contains anything applicable to this.
                              ⏯ Playground Link
                              https://www.typescriptlang.org/play/?#code/JYWwDg9gTgLgBALzgMyhEcDkCIBNMBQBApgB6SxwDGEAdgM7z1UAWxIAhnALyIB0EAEYArYlRgAKAN4E4cAPQAqRbLmK4AZXTE4tYFR0ApDQBEIVVXEXzVyCBABc-RlGC0A5hICUAGgIBfLyIaBnhSHjhmNk4+MA4oemJpO0csDkxAvhTLOVy8-ILCuXl5OAA9CrgWCAA3YlcPFHtI6oB3ejgYNjhjMwsgA
                              💻 Code
                              This is not the same issue as #50715, that issue is about type mappings that lose the JSDoc period.
                              I'm talking about what happens in the .d.ts file generated for source like this where JSDoc does survive type mapping:
                              importzfrom'zod'exportconstschema=z.object({/** * Some nice JSDoc */foo: z.string(),})constx=schema.parse({foo: 'a'}).foo// ^^^ hovering foo shows the JSDoc
                              🙁 Actual behavior
                              Hovering the parsed .foo in the source file displays the JSDoc for the property:
                              Image
                              But if I consume the same type from the generated .d.ts file, I don't get the JSDoc:
                              Image
                              🙂 Expected behavior
                              We should get the same JSDoc when consuming the .d.ts file as we do when consuming the source file it was generated from.
                              Additional information about the issue
                              If we look at the generated .d.ts the problem is clear: tsc isn't outputting JSDoc it has in memory for mapped type properties to the generated type literals:
                              importzfrom'zod';exportdeclareconstschema: z.ZodObject<{/** * Some nice JSDoc */foo: z.ZodString;},"strip",z.ZodTypeAny,{foo: string;// (tsc should have copied the JSDoc to this property)},{foo: string;// (and to this one)}>;//# sourceMappingURL=Schema.d.ts.map
                              It would at least be nice to have an option to output these copies of JSDoc, even though it would make the declaration file bigger.
                              Activity
                              Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
                              Metadata
                              Metadata
                              Assignees
                              No one assigned
                                Labels
                                Domain: Declaration EmitThe issue relates to the emission of d.ts filesHelp WantedYou can do thisPossible ImprovementThe current behavior isn't wrong, but it's possible to see that it might be better in some cases
                                Type
                                No type
                                Projects
                                No projects
                                  Milestone
                                  Relationships
                                  None yet
                                  Development
                                  No branches or pull requests
                                  Issue actions