Compiler Options.md

Compiler Options

Option	Type	Default	Description
--allowJs	boolean	false	Allow JavaScript files to be compiled.
--allowSyntheticDefaultImports	boolean	module === "system"	Allow default imports from modules with no default export. This does not affect code emit, just typechecking.
--allowUnreachableCode	boolean	false	Do not report errors on unreachable code.
--allowUnusedLabels	boolean	false	Do not report errors on unused labels.
--alwaysStrict	boolean	false	Parse in strict mode and emit "use strict" for each source file
--baseUrl	string		Base directory to resolve non-relative module names. See [Module Resolution documentation](./Module Resolution.md#base-url) for more details.
--charset	string	"utf8"	The character set of the input files.
--checkJs	boolean	false	Report errors in .js files. Use in conjunction with --allowJs.
--declaration -d	boolean	false	Generates corresponding .d.ts file.
--declarationDir	string		Output directory for generated declaration files.
--diagnostics	boolean	false	Show diagnostic information.
--disableSizeLimit	boolean	false	Disable size limitation on JavaScript project.
--downlevelIteration	boolean	false	Provide full support for iterables in for..of, spread and destructuring when targeting ES5 or ES3.
--emitBOM	boolean	false	Emit a UTF-8 Byte Order Mark (BOM) in the beginning of output files.
--emitDecoratorMetadata[1]	boolean	false	Emit design-type metadata for decorated declarations in source. See issue #2577 for details.
--experimentalDecorators[1]	boolean	false	Enables experimental support for ES decorators.
--forceConsistentCasingInFileNames	boolean	false	Disallow inconsistently-cased references to the same file.
--help -h			Print help message.
--importHelpers	boolean	false	Import emit helpers (e.g. __extends, __rest, etc..) from tslib
--inlineSourceMap	boolean	false	Emit a single file with source maps instead of having a separate file.
--inlineSources	boolean	false	Emit the source alongside the sourcemaps within a single file; requires --inlineSourceMap or --sourceMap to be set.
--init			Initializes a TypeScript project and creates a tsconfig.json file.
--isolatedModules	boolean	false	Transpile each file as a separate module (similar to "ts.transpileModule").
--jsx	string	"Preserve"	Support JSX in .tsx files: "React" or "Preserve". See JSX.
--jsxFactory	string	"React.createElement"	Specify the JSX factory function to use when targeting react JSX emit, e.g. React.createElement or h.
--lib	string[]		List of library files to be included in the compilation. Possible values are: ► ES5 ► ES6 ► ES2015 ► ES7 ► ES2016 ► ES2017 ► ESNext ► DOM ► DOM.Iterable ► WebWorker ► ScriptHost ► ES2015.Core ► ES2015.Collection ► ES2015.Generator ► ES2015.Iterable ► ES2015.Promise ► ES2015.Proxy ► ES2015.Reflect ► ES2015.Symbol ► ES2015.Symbol.WellKnown ► ES2016.Array.Include ► ES2017.object ► ES2017.SharedMemory ► esnext.asynciterable Note: If --lib is not specified a default library is injected. The default library injected is: ► For --target ES5: DOM,ES5,ScriptHost ► For --target ES6: DOM,ES6,DOM.Iterable,ScriptHost
--listEmittedFiles	boolean	false	Print names of generated files part of the compilation.
--listFiles	boolean	false	Print names of files part of the compilation.
--locale	string	(platform specific)	The locale to use to show error messages, e.g. en-us.
--mapRoot	string		Specifies the location where debugger should locate map files instead of generated locations. Use this flag if the .map files will be located at run-time in a different location than the .js files. The location specified will be embedded in the sourceMap to direct the debugger where the map files will be located.
--maxNodeModuleJsDepth	number	0	The maximum dependency depth to search under node_modules and load JavaScript files. Only applicable with --allowJs.
--module -m	string	target === "ES6" ? "ES6" : "CommonJS"	Specify module code generation: "None", "CommonJS", "AMD", "System", "UMD", "ES6", or "ES2015". ► Only "AMD" and "System" can be used in conjunction with --outFile. ► "ES6" and "ES2015" values may be used when targeting "ES5" or lower.
--moduleResolution	string	`module === "AMD"	"System"
--newLine	string	(platform specific)	Use the specified end of line sequence to be used when emitting files: "crlf" (windows) or "lf" (unix)."
--noEmit	boolean	false	Do not emit outputs.
--noEmitHelpers	boolean	false	Do not generate custom helper functions like __extends in compiled output.
--noEmitOnError	boolean	false	Do not emit outputs if any errors were reported.
--noFallthroughCasesInSwitch	boolean	false	Report errors for fallthrough cases in switch statement.
--noImplicitAny	boolean	false	Raise error on expressions and declarations with an implied any type.
--noImplicitReturns	boolean	false	Report error when not all code paths in function return a value.
--noImplicitThis	boolean	false	Raise error on this expressions with an implied any type.
--noImplicitUseStrict	boolean	false	Do not emit "use strict" directives in module output.
--noLib	boolean	false	Do not include the default library file (lib.d.ts).
--noResolve	boolean	false	Do not add triple-slash references or module import targets to the list of compiled files.
--noUnusedLocals	boolean	false	Report errors on unused locals.
--noUnusedParameters	boolean	false	Report errors on unused parameters.
--out	string		DEPRECATED. Use --outFile instead.
--outDir	string		Redirect output structure to the directory.
--outFile	string		Concatenate and emit output to single file. The order of concatenation is determined by the list of files passed to the compiler on the command line along with triple-slash references and imports. See output file order documentation for more details.
paths[2]	Object		List of path mapping entries for module names to locations relative to the baseUrl. See [Module Resolution documentation](./Module Resolution.md#path-mapping) for more details.
--preserveConstEnums	boolean	false	Do not erase const enum declarations in generated code. See const enums documentation for more details.
--pretty[1]	boolean	false	Stylize errors and messages using color and context.
--project -p	string		Compile a project given a valid configuration file. The argument can be a file path to a valid JSON configuration file, or a directory path to a directory containing a tsconfig.json file. See tsconfig.json documentation for more details.
--reactNamespace	string	"React"	DEPRECATED. Use --jsxFactory instead. Specifies the object invoked for createElement and __spread when targeting "react" JSX emit.
--removeComments	boolean	false	Remove all comments except copy-right header comments beginning with /*!
--rootDir	string	(common root directory is computed from the list of input files)	Specifies the root directory of input files. Only use to control the output directory structure with --outDir.
rootDirs[2]	string[]		List of root folders whose combined content represent the structure of the project at runtime. See [Module Resolution documentation](./Module Resolution.md#virtual-directories-with-rootdirs) for more details.
--skipDefaultLibCheck	boolean	false	DEPRECATED. Use --skipLibCheck instead. Skip type checking of [default library declaration files](./Triple-Slash Directives.md#-reference-no-default-libtrue).
--skipLibCheck	boolean	false	Skip type checking of all declaration files (*.d.ts).
--sourceMap	boolean	false	Generates corresponding .map file.
--sourceRoot	string		Specifies the location where debugger should locate TypeScript files instead of source locations. Use this flag if the sources will be located at run-time in a different location than that at design-time. The location specified will be embedded in the sourceMap to direct the debugger where the source files will be located.
--strict	boolean	false	Enable all strict type checking options. Enabling --strict enables --noImplicitAny, --noImplicitThis, --alwaysStrict and --strictNullChecks.
--strictNullChecks	boolean	false	In strict null checking mode, the null and undefined values are not in the domain of every type and are only assignable to themselves and any (the one exception being that undefined is also assignable to void).
--stripInternal[1]	boolean	false	Do not emit declarations for code that has an /** @internal */ JSDoc annotation.
--suppressExcessPropertyErrors	boolean	false	Suppress excess property checks for object literals.
--suppressImplicitAnyIndexErrors	boolean	false	Suppress --noImplicitAny errors for indexing objects lacking index signatures. See issue #1232 for more details.
--target -t	string	"ES3"	Specify ECMAScript target version: "ES3" (default), "ES5", "ES6"/"ES2015", "ES2016", "ES2017" or "ESNext". Note: "ESNext" targets latest supported ES proposed features.
--traceResolution	boolean	false	Report module resolution log messages.
--types	string[]		List of names of type definitions to include. See @types, --typeRoots and --types for more details.
--typeRoots	string[]		List of folders to include type definitions from. See @types, --typeRoots and --types for more details.
--version -v			Print the compiler's version.
--watch -w			Run the compiler in watch mode. Watch input files and trigger recompilation on changes.

• ^[1] These options are experimental.
• ^[2] These options are only allowed in tsconfig.json, and not through command-line switches.

Related

• Setting compiler options in tsconfig.json files.
• Setting compiler options in [MSBuild projects](./Compiler Options in MSBuild.md).