A Summary of TypeScript Configuration (tsconfig.json)

TypeScript

a year ago / 2 years ago

# tsconfig.json

The tsconfig.json file specifies how the TypeScript compiler converts your project to JS.

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{
  "files": ["node_modules/my-library/index.ts"],
  "exclude": ["node_modules", "dist"],
  "include": ["src/**/*"],
  "extends": "config/base.json",
  "compilerOptions": {}
}

tsconfig.json example

Option	Priority	Description
files	1	List of individual files to compile (extensions required!)
exclude	2	List of file paths to exclude from compilation
include	3	List of file paths to compile You can omit the `.ts`, `.tsx`, and `.d.ts` extensions, and `.js` and `.jsx` are added when `allowJS: true`
extends	-	Another TS configuration to inherit from
compilerOptions	-	Specifies compiler options

# CompilerOptions

Here are the main options you can use in CompilerOptions.

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{
  "compilerOptions": {
    "target": "ES2015",
    "module": "ESNext",
    "moduleResolution": "Node",
    "jsx": "preserve",
    "strict": true,
    "esModuleInterop": true,
    "lib": ["ESNext", "DOM"]
  }
}

compilerOptions example

Option	Default	Description
target	`"ES3"`	Specifies the ES version to compile to.
lib	-	Specifies the libraries to use in compilation.
module	`"CommonJS"`	Specifies the module system.
moduleResolution	`"Node"`	Specifies the module resolution strategy. `"NodeNext"` supports the `exports` field and conditional resolution. `"bundler"` is a resolution strategy tailored to bundlers such as Vite and Webpack.
esModuleInterop	`false`	Enables ESM module compatibility.
isolatedModules	`false`	Compiles every file as a module, and raises an error if a file has no `import` or `export`.
moduleDetection	-	Specifies how modules are detected. `"force"` treats every file as a module to prevent global scope conflicts.
allowSyntheticDefaultImports	`true`	Allows default imports from modules that have no default export (`export default`).
allowImportingTsExtensions	`false`	Lets you use files with the `.ts` and `.tsx` extensions directly in `import` statements.
baseUrl	-	Specifies the base path used for module resolution.
paths	-	Specifies path aliases used for module resolution.
types	-	Specifies the list of `@types` packages the compiler references; packages not listed are ignored.
typeRoots	`["./node_modules/@types"]`	Specifies the list of paths to type declarations (`.d.ts`) the compiler references; paths not listed are ignored.
allowJS	`false`	Allows compiling JS files.
checkJs	`false`	Whether to report errors in `.js` files. Only takes effect when `allowJS` is `true`.
jsx	`"preserve"`	Specifies how JSX is compiled. `"react-jsx"` compiles with the new JSX Transform of React 17+.
declaration	`true`	Whether to generate declaration files (`*.d.ts`) that contain the type information of all TS (JS) files.
declarationMap	`false`	Whether to generate source map files (`.d.ts.map`) along with the `.d.ts` files. Useful for jumping to the source code while debugging.
sourceMap	`false`	Whether to generate source map files. Lets debugging tools and the like show the original TS file of a JS file.
noEmit	`false`	Doesn't generate output files (`.js`, `.d.ts`, and so on) after compilation. Use it when you only want to run type checks.
skipLibCheck	`false`	Skips type checking of `.d.ts` files. Ignores errors in third-party libraries and speeds up builds.
strict	`false`	Enables stricter type checking. Includes all strict options (`noImplicitAny`, `strictNullChecks`, and so on).
noImplicitAny	`false`	(strict) Enables checks for implicit `any` types.
noImplicitThis	`false`	(strict) Enables checks for implicit `this` types.
strictNullChecks	`false`	(strict) Enables strict `null` and `undefined` type checks.
strictFunctionTypes	`false`	(strict) Enables strict type checks for function parameters.
strictPropertyInitialization	`false`	(strict) Enables strict checks for class property initialization.
strictBindCallApply	`false`	(strict) Enables strict argument checks for the `bind`, `call`, and `apply` methods.
noUnusedLocals	`false`	Raises an error when there are unused local variables.
noUnusedParameters	`false`	Raises an error when there are unused function parameters.
noFallthroughCasesInSwitch	`false`	Forbids fall-through, where a `case` block of a `switch` statement falls into the next `case`, to prevent logic errors.
noUncheckedIndexedAccess	`false`	Includes the possibility of `undefined` in the type when you access an object by index.
noUncheckedSideEffectImports	`false`	Raises an error when an `import` that triggers a module's side effects isn't checked. Strengthens type safety (TypeScript 5.0+).
useDefineForClassFields	`false`	Follows the ECMAScript standard (`defineProperty`) behavior when declaring class fields. The default is `true` with `target: "ES2022"` or higher.
resolveJsonModule	`false`	Allows importing `.json` files as modules.
tsBuildInfoFile	`.tsbuildinfo`	Specifies the path of the `.tsbuildinfo` file for incremental compilation (recompiling only what changed since the previous compilation).
verbatimModuleSyntax	`false`	Interprets ES module (ECMAScript Modules) syntax more strictly and accurately