lask

lask is a build tool for TypeScript libraries. It uses esbuild to build and bundle code and tsc to generate types. It is pretty opinionated. You might use it as a reference for building your own mini build tool.

Installation

npm install lask --dev

or

yarn add lask --dev

Usage

• Install lask to your project's devDependencies.
• Run yarn lask to build your project, or yarn lask -d to start your project in development mode.

If you like what you get, add lask to your package.json's scripts section:

{
  "scripts": {
    "build": "lask",
    "dev": "lask -d",
    "test": "lask test"
  }
}

Configuration

By default, lask expects your root directory to have:

• source code in the src directory
• output in the dist directory
• a tsconfig.json file in the root directory
• a tsconfig.dev.json file in the root directory
• a tsconfig.build.json file in the root directory
• a package.json with the following fields:

You can configure lask by creating a lask.config.json (sorry) in your project's root directory.

This config can include some or all of the following properties:

interface Options {
  isDev: boolean
  isNode: boolean
  entryPoints: string[]
  outDir: string
  clean: boolean
  external: {
    dependencies: boolean
    devDependencies: boolean
    peerDependencies: boolean
  }
  target: string
  format: 'esm' | 'cjs' | ('esm' | 'cjs')[]
  devFormat: 'esm' | 'cjs'
  devConfig: string
  buildConfig: string
  define: { [key: string]: string }
  calculateSize: boolean
}

For example:

{
  "isNode": true,
  "entryPoints": ["./src/index.ts"],
  "clean": true,
  "outDir": "dist",
  "external": {
    "dependencies": true,
    "devDependencies": true,
    "peerDependencies": true
  },
  "devConfig": "tsconfig.dev.json",
  "buildConfig": "tsconfig.build.json",
  "format": ["cjs", "esm"],
  "calculateSize": true
}

isNode

Whether to build / develop for node, rather than neutral JavaScript.

outDir

Where to place the output files. By default, this is dist. This means that your package.json should look like:

  "main": "./dist/index.js",
  "module": "./dist/index.mjs",
  "types": "./dist/index.d.ts",
  "source": "./src/index.ts",

If you set a different value for outDir, be sure to also update those fields in your package.json.

buildConfig

The location of the tsconfig file to use for lask. Defaults to tsconfig.build.json.

devConfig

The location of the tsconfig file to use for lask -d. Defaults to tsconfig.dev.json.

clean

Whether to remove the dist folder before building. Defaults to true.

external

By default, all three options here are set to true, which means that lask will exclude all dependencies / peerDependencies / devDependencies from the bundled output.

define

Passed to esbuild's define option. By default, define is set to either { "process.env.NODE_ENV": "production" } or { "process.env.NODE_ENV": "development" } depending on the isDev option.

format

Whether to build to "esm", "cjs", or ["cjs", "esm"]. Defaults to ["cjs", "esm"].

calculateSize

Whether to calculate the size of the output for each format. Defaults to true.

Troubleshooting

Path aliases aren't being converted?

Be sure that the outDir in your tsconfig.json (or tsconfig.build.json, etc.) is pointing to the correct folder. If you're outputting types to ./dist but your tsconfig.json has an outDir set to ./dist/types, the conversion won't work.

License

This project is MIT licensed.

Author

• Steve Ruiz (Github / Twitter)