Compiler options

Typically, the first step in a new TypeScript project is to add in a tsconfig.json file. This file defines the project and compiler settings, for instance, files and libraries to be included in the compilation, output structure, module code generation, and so on. A typical configuration in tsconfig.json for Angular 2+ projects looks like the following:

{
  "compilerOptions": {
    "target": "es5",
    "module": "es2015",
    "moduleResolution": "node",
    "noImplicitAny": true,
    "sourceMap": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "outDir": "dist",
    "lib": ["es2015", "dom"]
  },
  "types": ["node"],
  "exclude": ["node_modules", "dist"]
}

The listed compiler settings are described as follows. A full list of all options is available at the TypeScript documentation page (https://www.typescriptlang.org/docs/handbook/compiler-options.html).

Option Type Default Description target string ES3 This specifies ECMAScript target version: ES3, ES5, ES2015, ES2016, and ES2017. module string ES6 if target is "ES6" and CommonJS otherwise This specifies the format of module code generation: None, CommonJS, AMD, System, UMD, ES6, or ES2015. moduleResolution string Classic if module is "AMD," System, ES6, and Node otherwise This determines how modules get resolved. Either Node for Node.js style resolution or Classic. noImplicitAny boolean false This raises errors on expressions and declarations with an implied any type. sourceMap boolean false This generates the corresponding .map file. This is useful if you want to debug original files. emitDecoratorMetadata boolean false This emits design type metadata for decorated declarations in source. You have to set this value to true if you want to develop web applications with Angular. experimentalDecorators boolean false This enables experimental support for ECMAScript decorators. You have to set this value to true if you want to develop web applications with Angular. outDir string - This is the output directory for compiled files. lib string[] Refer to the documentation for more information. This is the list of library files to be included in the compilation. Refer to the documentation for more information. types string[] - This is the list of names of type definitions to include. exclude string[] - This is the list of (sub) directories excluded from the compilation.