tsconfig

Shared TypeScript configuration for fastify projects

Install

$ npm install --save-dev fastify-tsconfig

Usage

Create your own tsconfig.json in the projects' root folder and extend it from fastify-tsconfig, overriding or adding the desired settings. By default, no outDir is set (because of this issue), so be sure to add one.

Configuration module and moduleResolution

This configuration sets "module" and "moduleResolution" to NodeNext. This means that TypeScript will read the nearest package.json file in the scope and search for the "type" field or the absence of it.

If type is not set or is "type": "commonjs" the emitted code will be CommonJS, with .js extension. Moreover, tsc will complain if ESM-only properties/features are used in source files. If you want to emit .mjs files, use the .mts extension. On the other hand, if "type": "module" is set, the sources will be compiled to the ESM with the .js extension. In this case, if you want to emit .cjs files, use the .cts extension for the source file.

The "following the Node.js rules" goes also for the package.json exports field. If type is set, regardless of the value, TypeScript will check the exports field to know where the compiled code and the types are located. If the type field is not set, it will check for the main and types fields.

CommonJS example

package.json

{
  "name": "my-package",
  "type": "commonjs",
  "main": "dist/index.js", // this is for older Node.js versions
  "types": "dist/index.d.ts", // this is optional and can be omitted
  "exports": {
    "import": "./dist/index.js",
    "require": "./dist/index.js",
    "types": "./dist/index.d.ts" // this is optional and can be omitted
 }
}

tsconfig.json

{
 "extends": "fastify-tsconfig",
 "compilerOptions": {
    "outDir": "dist",
    "sourceMap": true
  },
  "include": [
    "src/**/*.ts"
  ]
}

ESM example

package.json

{
  "name": "my-package",
  "type": "module",
  "main": "dist/index.js", // this is for older Node.js versions
  "types": "dist/index.d.ts", // this is optional and can be omitted
  "exports": {
    "import": "./dist/index.js",
    "require": "./dist/index.js",
    "types": "./dist/index.d.ts" // this is optional and can be omitted
 }
}

tsconfig.json

{
 "extends": "fastify-tsconfig",
 "compilerOptions": {
    "outDir": "dist",
    "sourceMap": true
  },
  "include": [
    "src/**/*.ts"
  ]
}

Extending this configuration

Depending on the type of the project, you should add the following settings.

Application

tsconfig.json

{
 "extends": "fastify-tsconfig",
 "compilerOptions": {
    "outDir": "dist",
    "sourceMap": true
 },
 "include": [
    "src/**/*.ts"
 ]
}

NPM Package

tsconfig.json

{
 "extends": "fastify-tsconfig",
 "compilerOptions": {
    "outDir": "dist",
    "declaration": true
 },
 "include": [
    "src/**/*.ts"
 ]
}

Monorepo Package

tsconfig.json

{
 "extends": "fastify-tsconfig",
 "compilerOptions": {
    "outDir": "dist",
    "declarationMap": true,
    "composite": true
 },
 "include": [
    "src/**/*.ts"
 ]
}

Check the other settings here

Configuration target

The configuration targets ES2022, which is supported in Node.js 16 and later. Only one feature still needs to be implemented: RegExp Match Indices shows up in flags. However, using ES2022 as a target makes widely used features not being compiled. To target an older version, override the target property.

License

Licensed under MIT.

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Inspired by: sindresorhus/tsconfig