Overview

The presence of a tsconfig.json file in a directory indicates that the directory is the root of a TypeScript project. The tsconfig.json file specifies the root files and the compiler options required to compile the project. A project is compiled in one of the following ways:

Using tsconfig.json

  • By invoking tsc with no input files, in which case the compiler searches for the tsconfig.json file starting in the current directory and continuing up the parent directory chain.
  • By invoking tsc with no input files and a --project (or just -p) command line option that specifies the path of a directory containing a tsconfig.json file, or a path to a valid .json file containing the configurations.

When input files are specified on the command line, tsconfig.json files are ignored.

Examples

Example tsconfig.json files:

  • Using the "files" property

    {
        "compilerOptions": {
            "module": "commonjs",
            "noImplicitAny": true,
            "removeComments": true,
            "preserveConstEnums": true,
            "sourceMap": true
        },
        "files": [
            "core.ts",
            "sys.ts",
            "types.ts",
            "scanner.ts",
            "parser.ts",
            "utilities.ts",
            "binder.ts",
            "checker.ts",
            "emitter.ts",
            "program.ts",
            "commandLineParser.ts",
            "tsc.ts",
            "diagnosticInformationMap.generated.ts"
        ]
    }
    
  • Using the "include" and "exclude" properties

    {
        "compilerOptions": {
            "module": "system",
            "noImplicitAny": true,
            "removeComments": true,
            "preserveConstEnums": true,
            "outFile": "../../built/local/tsc.js",
            "sourceMap": true
        },
        "include": [
            "src/**/*"
        ],
        "exclude": [
            "node_modules",
            "**/*.spec.ts"
        ]
    }
    

Details

The "compilerOptions" property can be omitted, in which case the compiler’s defaults are used. See our full list of supported Compiler Options.

The "files" property takes a list of relative or absolute file paths. The "include" and "exclude" properties take a list of glob-like file patterns. The supported glob wildcards are:

  • * matches zero or more characters (excluding directory separators)
  • ? matches any one character (excluding directory separators)
  • **/ recursively matches any subdirectory

If a segment of a glob pattern includes only * or .*, then only files with supported extensions are included (e.g. .ts, .tsx, and .d.ts by default with .js and .jsx if allowJs is set to true).

If the "files" and "include" are both left unspecified, the compiler defaults to including all TypeScript (.ts, .d.ts and .tsx) files in the containing directory and subdirectories except those excluded using the "exclude" property. JS files (.js and .jsx) are also included if allowJs is set to true. If the "files" or "include" properties are specified, the compiler will instead include the union of the files included by those two properties. Files in the directory specified using the "outDir" compiler option are always excluded unless explicitly included via the "files" property (even when the “exclude” property is specified).

Files included using "include" can be filtered using the "exclude" property. However, files included explicitly using the "files" property are always included regardless of "exclude". The "exclude" property defaults to excluding the node_modules, bower_components, jspm_packages and <outDir> directories when not specified.

Any files that are referenced by files included via the "files" or "include" properties are also included. Similarly, if a file B.ts is referenced by another file A.ts, then B.ts cannot be excluded unless the referencing file A.ts is also specified in the "exclude" list.

A tsconfig.json file is permitted to be completely empty, which compiles all files included by default (as described above) with the default compiler options.

Compiler options specified on the command line override those specified in the tsconfig.json file.

@types, typeRoots and types

By default all visible@types” packages are included in your compilation. Packages in node_modules/@types of any enclosing folder are considered visible; specifically, that means packages within ./node_modules/@types/, ../node_modules/@types/, ../../node_modules/@types/, and so on.

If typesRoots is specified, only packages under typeRoots will be included. For example:

{
   "compilerOptions": {
       "typeRoots" : ["./typings"]
   }
}

This config file will include all packages under ./typings, and no packages from ./node_modules/@types.

If types is specified, only packages listed will be included. For instance:

{
   "compilerOptions": {
       "types" : ["node", "lodash", "express"]
   }
}

This tsconfig.json file will only include ./node_modules/@types/node, ./node_modules/@types/lodash and ./node_modules/@types/express. Other packages under node_modules/@types/* will not be included.

Specify "types": [] to disable automatic inclusion of @types packages.

Keep in mind that automatic inclusion is only important if you’re using files with global declarations (as opposed to files declared as modules). If you use an import "foo" statement, for instance, TypeScript may still look through node_modules & node_modules/@types folders to find the foo package.

Configuration inheritance with extends

A tsconfig.json file can inherit configurations from another file using the extends property.

The extends is a top-level property in tsconfig.json (alongside compilerOptions, files, include, and exclude). extends’ value is a string containing a path to another configuration file to inherit from.

The configuration from the base file are loaded first, then overridden by those in the inheriting config file. If a circularity is encountered, we report an error.

files, include and exclude from the inheriting config file overwrite those from the base config file.

All relative paths found in the configuration file will be resolved relative to the configuration file they originated in.

For example:

configs/base.json:

{
  "compilerOptions": {
    "noImplicitAny": true,
    "strictNullChecks": true
  }
}

tsconfig.json:

{
  "extends": "./configs/base",
  "files": [
    "main.ts",
    "supplemental.ts"
  ]
}

tsconfig.nostrictnull.json:

{
  "extends": "./tsconfig",
  "compilerOptions": {
    "strictNullChecks": false
  }
}

compileOnSave

Setting a top-level property compileOnSave signals to the IDE to generate all files for a given tsconfig.json upon saving.

{
   "compileOnSave": true,
   "compilerOptions": {
       "noImplicitAny" : true
   }
}

This feature is currently supported in Visual Studio 2015 with TypeScript 1.8.4 and above, and atom-typescript plugin.

Schema

Schema can be found at: http://json.schemastore.org/tsconfig