Compiler Options

Using the CLI

Running tsc locally will compile the closest project defined by a tsconfig.json, you can compile a set of TypeScript files by passing in a glob of files you want.

# Run a compile based on a backwards look through the fs for a tsconfig.json tsc # Transpile just the index.ts with the compiler defaults tsc index.ts # Transpile any .ts files in the folder src, with the default settings tsc src/*.ts # Transpile any files referenced in with the compiler settings from tsconfig.production.json tsc --project tsconfig.production.json

Compiler Options

If you’re looking for more information about the compiler options in a tsconfig, check out the TSConfig Reference

Option Type Default Description
--allowJs boolean false Allow JavaScript files to be compiled.
--allowSyntheticDefaultImports boolean module === "system" or --esModuleInterop Allow default imports from modules with no default export. This does not affect code emit, just typechecking.
--allowUmdGlobalAccess boolean false Allow accessing UMD globals from modules.
--allowUnreachableCode boolean 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
--assumeChangesOnlyAffectDirectDependencies boolean false Have recompiles in --incremental and --watch assume that changes within a file will only affect files directly depending on it
--baseUrl string Base directory to resolve non-relative module names. See Module Resolution documentation for more details.
boolean false Builds this project and all of its dependencies specified by Project References. Note that this flag is not compatible with others on this page. See more here
--charset string "utf8" The character set of the input files.
--checkJs boolean false Report errors in .js files. Use in conjunction with --allowJs.
--composite boolean true Ensure TypeScript can determine where to find the outputs of the referenced project to compile project.
boolean false Generates corresponding .d.ts file.
--declarationDir string Output directory for generated declaration files.
--declarationMap boolean false Generates a sourcemap for each corresponding .d.ts file.
--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.
--emitDeclarationOnly boolean false Only emit .d.ts declaration files.
--emitDecoratorMetadata[1] boolean false Emit design-type metadata for decorated declarations in source. See issue #2577 for details.
--esModuleInterop boolean false Emit __importStar and __importDefault helpers for runtime babel ecosystem compatibility and enable --allowSyntheticDefaultImports for typesystem compatibility.
--experimentalDecorators[1] boolean false Enables experimental support for ES decorators.
--extendedDiagnostics boolean false Show verbose diagnostic information
--forceConsistentCasingInFileNames boolean false Disallow inconsistently-cased references to the same file.
--generateCpuProfile string profile.cpuprofile Generates a cpu profile at the given path. Passing an existing directory name instead of a file path will cause a timestamp-named profile to be generated in that directory instead.
Print help message.
--importHelpers boolean false Import emit helpers (e.g. __extends, __rest, etc..) from tslib
--incremental boolean true if composite is on, false otherwise Enable incremental compilation by reading/writing information from prior compilations to a file on disk. This file is controlled by the --tsBuildInfoFile flag.
--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 Perform additional checks to ensure that separate compilation (such as with transpileModule or @babel/plugin-transform-typescript) would be safe.
--jsx string Support JSX in .tsx files: "react", "preserve", "react-native". See JSX.
--jsxFactory string "React.createElement" Specify the JSX factory function to use when targeting react JSX emit, e.g. React.createElement or h.
--jsxFragmentFactory string "React.Fragment" Specify the JSX fragment factory function to use when targeting react JSX emit, e.g. Fragment.
--keyofStringsOnly boolean false Resolve keyof to string valued property names only (no numbers or symbols).
--lib string[] List of library files to be included in the compilation.
Possible values are:

Note: If --lib is not specified a default list of libraries are injected. The default libraries injected are:
► 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.
Possible values are:
► English (US): en
► Czech: cs
► German: de
► Spanish: es
► French: fr
► Italian: it
► Japanese: ja
► Korean: ko
► Polish: pl
► Portuguese(Brazil): pt-BR
► Russian: ru
► Turkish: tr
► Simplified Chinese: zh-CN
► Traditional Chinese: zh-TW
--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. This flag will not create the specified path and generate the map files in that location. Instead, create a post build step that moves the files to the specified path.
--maxNodeModuleJsDepth number 0 The maximum dependency depth to search under node_modules and load JavaScript files. Only applicable with --allowJs.
string target === "ES3" or "ES5" ? "CommonJS" : "ES6" Specify module code generation: "None", "CommonJS", "AMD", "System", "UMD", "ES6", "ES2015" or "ESNext".
► 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" or "UMD" or "System" or "ES6" ? "Classic" : "Node" Determine how modules get resolved. Either "Node" for Node.js/io.js style resolution, or "Classic". See Module Resolution documentation for more details.
--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.
--noErrorTruncation boolean false Do not truncate error messages.
--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 an 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.
--noStrictGenericChecks boolean false Disable strict checking of generic signatures in function types.
--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 for more details.
--preserveConstEnums boolean false Do not erase const enum declarations in generated code. See const enums documentation for more details.
--preserveSymlinks boolean false Do not resolve symlinks to their real path; treat a symlinked file like a real one.
--preserveWatchOutput boolean false Keep outdated console output in watch mode instead of clearing the screen
--pretty boolean true unless piping to another program or redirecting output to a file Stylize errors and messages using color and context.
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 /*!
--resolveJsonModule boolean false Include modules imported with .json extension.
--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 for more details.
--showConfig boolean false Rather than actually execute a build with the other input options and config files, show the final implied config file in the output.
--skipDefaultLibCheck boolean false DEPRECATED. Use --skipLibCheck instead.
Skip type checking of default library declaration files.
--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, --strictBindCallApply, --strictNullChecks, --strictFunctionTypes and --strictPropertyInitialization.
--strictBindCallApply boolean false Enable stricter checking of the bind, call, and apply methods on functions.
--strictFunctionTypes boolean false Disable bivariant parameter checking for function types.
--strictPropertyInitialization boolean false Ensure non-undefined class properties are initialized in the constructor. This option requires --strictNullChecks be enabled in order to take effect.
--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).
--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.
string "ES3" Specify ECMAScript target version:
"ES3" (default)

Note: "ESNext" targets latest supported ES proposed features.
--traceResolution boolean false Report module resolution log messages.
--tsBuildInfoFile string .tsbuildinfo Specify what file to store incremental build information in.
--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.
--useDefineForClassFields boolean false Emit class fields with ECMAScript-standard semantics.
Print the compiler’s version.
Run the compiler in watch mode. Watch input files and trigger recompilation on changes. The implementation of watching files and directories can be configured using environment variable. See configuring watch for more details.
  • [1] These options are experimental.
  • [2] These options are only allowed in tsconfig.json, and not through command-line switches.

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Last updated: Sep 28, 2020