tsc --init update

[Ryan Cavanaugh (RyanCavanaugh)]

Fixes#58420

Sample outputs

tsc --init

{
// Visit https://aka.ms/tsconfig to read more about this file"compilerOptions": {
// File Layout// "rootDir": "./src",// "outDir": "./dist",// Environment Settings// See also https://aka.ms/tsconfig_modules"module": "nodenext",
"target": "esnext",
"types": [],
// For nodejs:// "lib": ["esnext"],// "types": ["node"],// and npm install -D @types/node// Other Outputs"sourceMap": true,
"declaration": true,
"declarationMap": true,
// Stricter Typechecking Options"noUncheckedIndexedAccess": true,
"exactOptionalPropertyTypes": true,
// Style Options// "noImplicitReturns": true,// "noImplicitOverride": true,// "noUnusedLocals": true,// "noUnusedParameters": true,// "noFallthroughCasesInSwitch": true,// "noPropertyAccessFromIndexSignature": true,// Recommended Options"strict": true,
"jsx": "react-jsx",
"verbatimModuleSyntax": true,
"isolatedModules": true,
"noUncheckedSideEffectImports": true,
"moduleDetection": "force",
"skipLibCheck": true,
}
}

tsc --init --noImplicitAny false --target es2022 --lib dom --rootDir src --types mocha --noImplicitReturns

{
// Visit https://aka.ms/tsconfig to read more about this file"compilerOptions": {
// File Layout"rootDir": "src",
// "outDir": "./dist",// Environment Settings// See also https://aka.ms/tsconfig_modules"module": "nodenext",
"target": "es2022",
"types": ["mocha"],
"lib": ["dom"],
// For nodejs:// "lib": ["esnext"],// "types": ["node"],// and npm install -D @types/node// Other Outputs"sourceMap": true,
"declaration": true,
"declarationMap": true,
// Stricter Typechecking Options"noUncheckedIndexedAccess": true,
"exactOptionalPropertyTypes": true,
// Style Options"noImplicitReturns": true,
// "noImplicitOverride": true,// "noUnusedLocals": true,// "noUnusedParameters": true,// "noFallthroughCasesInSwitch": true,// "noPropertyAccessFromIndexSignature": true,// Recommended Options"strict": true,
"jsx": "react-jsx",
"verbatimModuleSyntax": true,
"isolatedModules": true,
"noUncheckedSideEffectImports": true,
"moduleDetection": "force",
"skipLibCheck": true,
"noImplicitAny": false,
}
}

[Copilot]

Pull Request Overview

Updates the --init logic to streamline how tsconfig.json is generated and simplify related tests and CLI handling. Key changes include:

• Refactored generateTSConfig signature and implementation to remove file list parameter and output clean, sectioned JSON.
• Updated writeConfigFile and test invocations to match new generateTSConfig signature.
• Added diagnostic message entries for each new section header.

Reviewed Changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 1 comment.

File	Description
src/compiler/commandLineParser.ts	Replaced old getCompilerOptionsDiffValue and rewritten generateTSConfig with new API.
src/compiler/executeCommandLine.ts	Updated writeConfigFile to call new generateTSConfig signature and cleaned output.
src/testRunner/unittests/config/initializeTSConfig.ts	Adjusted test helper to use new generateTSConfig(options, newLine) call.
src/compiler/diagnosticMessages.json	Inserted new diagnostic entries for section headers used in generated JSON.

Comments suppressed due to low confidence (1)

src/compiler/commandLineParser.ts:2930

• Consider appending a trailing newline to the generated config for consistency with existing baselines and editor tooling. For example: return result.join(newLine) + newLine;

 return result.join(newLine);

[Jake Bailey (jakebailey)]

I was like "oh no, hope nobody calls this", but no, it's all callers from 5+ years ago (https://github.com/search?q=%2Fts%28+as+%5B%5E%28%5D%2B%5C%29%29%3F%5C.generateTSConfig%5C%28%2F+-path%3Atestrunner&type=code)

[Sheetal Nandi (sheetalkamat)]

probably already discussed when i wasnt here, but declarationMap seems like overkill ? and additional cost?

[Jake Bailey (jakebailey)]

I'd suggest we just comment it out.

[Jake Bailey (jakebailey)]

Maybe a silly idea, but should we note the effect that this has?

[Jake Bailey (jakebailey)]

Is this intentional? I assume so?

[Jake Bailey (jakebailey)]

Outside what I commented, everything is looking great.

[Jake Bailey (jakebailey)]

In any case, giving this another +1 since it's what was spec'd out, but if we do want to drop declarationMap that's fine too.

[Rob Palmer (robpalme)]

There's a typo that caught my eye in the PR description. The code itself is fine.

 "target": "nodenext",

It should say "esnext"

[Jake Bailey (jakebailey)]

Edited it. And it should also have said module=nodenext