Compiler Options Reference

Overview

This page provides a comprehensive reference for all TypeScript compiler options extracted from the TypeScript source code (src/compiler/commandLineParser.ts).

All compiler options are specified in the compilerOptions section of your tsconfig.json file.

Language and Environment

Options that affect the JavaScript language version and runtime environment.

target

string

default:"ES3"

Set the JavaScript language version for emitted JavaScript and include compatible library declarations.Type:

"es3" | "es5" | "es2015" | "es2016" | "es2017" | "es2018" | "es2019" | "es2020" | "es2021" | "es2022" | "es2023" | "es2024" | "es2025" | "esnext"

Shorthand: -tSource: src/compiler/commandLineParser.ts:572-602

{
  "compilerOptions": {
    "target": "es2020"
  }
}

lib

string[]

Specify a set of bundled library declaration files that describe the target runtime environment.Common values: es5, es2015, es2020, esnext, dom, dom.iterable, webworker, scripthostSource: src/compiler/commandLineParser.ts:704-717

{
  "compilerOptions": {
    "lib": ["es2020", "dom", "dom.iterable"]
  }
}

All available lib options

JavaScript versions:

es5, es6/es2015, es2016, es2017, es2018, es2019, es2020, es2021, es2022, es2023, es2024, es2025, esnext

Host environments:

dom, dom.iterable, dom.asynciterable
webworker, webworker.importscripts, webworker.iterable, webworker.asynciterable
scripthost

Feature-specific libraries: Over 50 feature-specific libraries available (e.g., es2015.promise, es2020.bigint, esnext.decorators)Source: src/compiler/commandLineParser.ts:151-265

jsx

string

Specify what JSX code is generated.Type: "preserve" | "react-native" | "react" | "react-jsx" | "react-jsxdev"Source: src/compiler/commandLineParser.ts:740-755

{
  "compilerOptions": {
    "jsx": "react-jsx"
  }
}

jsxFactory

string

default:"React.createElement"

Specify the JSX factory function used when targeting React JSX emit.Source: src/compiler/commandLineParser.ts:1336-1341

jsxFragmentFactory

string

default:"React.Fragment"

Specify the JSX Fragment reference used for fragments when targeting React JSX emit.Source: src/compiler/commandLineParser.ts:1343-1348

jsxImportSource

string

default:"react"

Specify module specifier used to import the JSX factory functions when using jsx: react-jsx*.Source: src/compiler/commandLineParser.ts:1350-1360

moduleDetection

string

default:"auto"

Control what method is used to detect module-format JS files.Type: "auto" | "legacy" | "force"Source: src/compiler/commandLineParser.ts:1671-1682

experimentalDecorators

boolean

default:"false"

Enable experimental support for legacy experimental decorators.Source: src/compiler/commandLineParser.ts:1314-1322

emitDecoratorMetadata

boolean

default:"false"

Emit design-type metadata for decorated declarations in source files.Source: src/compiler/commandLineParser.ts:1324-1332

noLib

boolean

default:"false"

Disable including any library files including the default lib.d.ts.Source: src/compiler/commandLineParser.ts:1448-1457

useDefineForClassFields

boolean

default:"true for ES2022+"

Emit ECMAScript-standard-compliant class fields.Source: src/compiler/commandLineParser.ts:1632-1640

Modules

Options that affect module resolution and output.

module

string

Specify what module code is generated.Type:

"none" | "commonjs" | "amd" | "system" | "umd" | "es6" | "es2015" | "es2020" | "es2022" | "esnext" | "node16" | "nodenext" | "preserve"

Shorthand: -mSource: src/compiler/commandLineParser.ts:605-635

{
  "compilerOptions": {
    "module": "NodeNext"
  }
}

moduleResolution

string

Specify how TypeScript looks up a file from a given module specifier.Type: "node10" | "node" | "classic" | "node16" | "nodenext" | "bundler"Default: "nodenext" if module is nodenext, "node16" if module is node16, otherwise "bundler"Source: src/compiler/commandLineParser.ts:1097-1114

{
  "compilerOptions": {
    "moduleResolution": "bundler"
  }
}

baseUrl

string

Specify the base directory to resolve non-relative module names.Source: src/compiler/commandLineParser.ts:1116-1122

paths

object

Specify a set of entries that re-map imports to additional lookup locations.Source: src/compiler/commandLineParser.ts:1126-1134

{
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "@/*": ["src/*"],
      "@shared/*": ["../shared/src/*"]
    }
  }
}

rootDir

string

Specify the root folder within your source files.Default: Computed from the list of input filesSource: src/compiler/commandLineParser.ts:782-792

rootDirs

string[]

Allow multiple folders to be treated as one when resolving modules.Source: src/compiler/commandLineParser.ts:1138-1152

typeRoots

string[]

Specify multiple folders that act like ./node_modules/@types.Source: src/compiler/commandLineParser.ts:1154-1165

types

string[]

Specify type package names to be included without being referenced in a source file.Source: src/compiler/commandLineParser.ts:1167-1178

{
  "compilerOptions": {
    "types": ["node", "jest"]
  }
}

resolveJsonModule

boolean

default:"false"

Enable importing .json files.Source: src/compiler/commandLineParser.ts:1362-1368

resolvePackageJsonExports

boolean

default:"true for node16/nodenext/bundler"

Use the package.json ‘exports’ field when resolving package imports.Source: src/compiler/commandLineParser.ts:1247-1253

resolvePackageJsonImports

boolean

default:"true for node16/nodenext/bundler"

Use the package.json ‘imports’ field when resolving imports.Source: src/compiler/commandLineParser.ts:1255-1261

customConditions

string[]

Conditions to set in addition to the resolver-specific defaults when resolving imports.Source: src/compiler/commandLineParser.ts:1263-1272

moduleSuffixes

string[]

List of file name suffixes to search when resolving a module.Source: src/compiler/commandLineParser.ts:1216-1226

allowImportingTsExtensions

boolean

default:"false"

Allow imports to include TypeScript file extensions. Requires --moduleResolution bundler and either --noEmit or --emitDeclarationOnly.Source: src/compiler/commandLineParser.ts:1228-1236

rewriteRelativeImportExtensions

boolean

default:"false"

Rewrite .ts, .tsx, .mts, and .cts file extensions in relative import paths to their JavaScript equivalent in output files.Source: src/compiler/commandLineParser.ts:1238-1245

allowArbitraryExtensions

boolean

default:"false"

Enable importing files with any extension, provided a declaration file is present.Source: src/compiler/commandLineParser.ts:1370-1376

noResolve

boolean

default:"false"

Disallow imports, requires, or <reference>s from expanding the number of files TypeScript should add to a project.Source: src/compiler/commandLineParser.ts:1459-1468

noUncheckedSideEffectImports

boolean

default:"true"

Check side effect imports.Source: src/compiler/commandLineParser.ts:1274-1281

Emit

Options that affect JavaScript emit.

outFile

string

Specify a file that bundles all outputs into one JavaScript file. If declaration is true, also designates a file that bundles all .d.ts output.Source: src/compiler/commandLineParser.ts:757-768

outDir

string

Specify an output folder for all emitted files.Source: src/compiler/commandLineParser.ts:770-780

{
  "compilerOptions": {
    "outDir": "./dist"
  }
}

declaration

boolean

default:"false (true if composite is set)"

Generate .d.ts files from TypeScript and JavaScript files in your project.Shorthand: -dSource: src/compiler/commandLineParser.ts:477-487

declarationMap

boolean

default:"false"

Create sourcemaps for d.ts files.Source: src/compiler/commandLineParser.ts:489-497

declarationDir

string

Specify the output directory for generated declaration files.Source: src/compiler/commandLineParser.ts:1548-1558

emitDeclarationOnly

boolean

default:"false"

Only output d.ts files and not JavaScript files.Source: src/compiler/commandLineParser.ts:499-508

sourceMap

boolean

default:"false"

Create source map files for emitted JavaScript files.Source: src/compiler/commandLineParser.ts:510-518

inlineSourceMap

boolean

default:"false"

Include sourcemap files inside the emitted JavaScript.Source: src/compiler/commandLineParser.ts:520-527

sourceRoot

string

Specify the root path for debuggers to find the reference source code.Source: src/compiler/commandLineParser.ts:1285-1292

mapRoot

string

Specify the location where debugger should locate map files instead of generated locations.Source: src/compiler/commandLineParser.ts:1294-1301

inlineSources

boolean

default:"false"

Include source code in the sourcemaps inside the emitted JavaScript.Source: src/compiler/commandLineParser.ts:1303-1310

removeComments

boolean

default:"false"

Disable emitting comments.Source: src/compiler/commandLineParser.ts:817-825

noEmit

boolean

default:"false"

Disable emitting files from a compilation.Source: src/compiler/commandLineParser.ts:539-546

noEmitOnError

boolean

default:"false"

Disable emitting files if any type checking errors are reported.Source: src/compiler/commandLineParser.ts:1529-1537

noEmitHelpers

boolean

default:"false"

Disable generating custom helper functions like __extends in compiled output.Source: src/compiler/commandLineParser.ts:1520-1527

importHelpers

boolean

default:"false"

Allow importing helper functions from tslib once per project, instead of including them per-file.Source: src/compiler/commandLineParser.ts:827-835

importsNotUsedAsValues

string

default:"remove"

Specify emit/checking behavior for imports that are only used for types.Type: "remove" | "preserve" | "error"Source: src/compiler/commandLineParser.ts:837-849

downlevelIteration

boolean

default:"false"

Emit more compliant, but verbose and less performant JavaScript for iteration.Source: src/compiler/commandLineParser.ts:851-858

preserveConstEnums

boolean

default:"false"

Disable erasing const enum declarations in generated code.Source: src/compiler/commandLineParser.ts:1539-1546

stripInternal

boolean

default:"false"

Disable emitting declarations that have @internal in their JSDoc comments.Source: src/compiler/commandLineParser.ts:1470-1477

newLine

string

default:"lf"

Set the newline character for emitting files.Type: "crlf" | "lf"Source: src/compiler/commandLineParser.ts:1426-1437

emitBOM

boolean

default:"false"

Emit a UTF-8 Byte Order Mark (BOM) in the beginning of output files.Source: src/compiler/commandLineParser.ts:1417-1424

Type Checking

Options that affect type checking behavior.

strict

boolean

default:"true"

Enable all strict type-checking options.Source: src/compiler/commandLineParser.ts:906-917

Enabling strict is equivalent to enabling all of the strict mode family options:

noImplicitAny
strictNullChecks
strictFunctionTypes
strictBindCallApply
strictPropertyInitialization
noImplicitThis
useUnknownInCatchVariables
alwaysStrict
strictBuiltinIteratorReturn