ts-lib-starter

Boilerplate for your next TypeScript library. Build with speed.

Features

pnpm

A fast and efficient package manager. Packages are linked from a single, global store.

tsup

A quick, easy-to-use, and zero config bundler powered by esbuild. This allows for dual publishing esm and cjs . It also produces only one type definition file for each entrypoint.

vitest

A testing framework. Uses Vite for building your code, so look through the Vite docs if you need to add plugins.

dprint

A pluggable and configurable code formatting platform written in Rust. Faster alternative to Prettier.

ESLint and TypeScript ESLint

Linter that helps you find problems in your code.

npm-run-all

Run dprint, TypeScript, and ESLint checks in parallel.

Github Actions

Run all your checks on each commit.

Ensure all files are formatted before they are committed and run linters on changed files.

Renovate

Automatically opens PRs to update dependencies. Automerges patch and minor updates, but not major updates or any typescript updates. Also pins all devDependencies) to use exact versions (no ^ before version signifying that the latest patch version can be matched, only the version specified can be used).

Usage

This is esm-first, meaning you should write esm and it is transpiled to both esm and cjs. For example, use:

import path from 'path'
import { fileURLToPath } from 'url'

const __dirname = path.dirname(fileURLToPath(import.meta.url))

instead of __dirname.

Setup

1. Install pnpm

2. Grant Renovate access to your GitHub repos

3. Copy the repo, replace mypackage with your repository name:

pnpx degit sachinraja/ts-lib-starter mypackage && cd mypackage

4. Search and replace all instances of ts-lib-starter with your package name. Remove LICENSE or replace it with your own.

5. Install dependencies:

pnpm i

6. Lint package:

pnpm lint

7. Test package:

pnpm t

Note that there is a workflow in .github/workflows/test.yml that will run on each commit if you push it to GitHub.

Publishing

Run pnpm publish to publish the package. Make sure the version is what you want to publish before publishing. Building the package (in a prepublishOnly script) and setting the relevant package.json attributes are already done. Note that sideEffects is set to false, so bundlers like Webpack can tree shake the package:

A "side effect" is defined as code that performs a special behavior when imported, other than exposing one or more exports. An example of this are polyfills, which affect the global scope and usually do not provide an export.

Entry Points

An entry point is a path that modules from your package can be imported from. The default entry point for this starter is ., which simply means that src/index.ts can be imported as ts-lib-starter (your package name).

If you want to add an entrypoint, you must do the following:

1. Specify the path you want to users to import your module from. For this example, I will use the file src/constants.ts and expose the entry point as ts-lib-starter/constants. Add the following in package.json exports:

"exports": {
    ".": {
        // ...
    },
    "./constants": {
        "import": "./dist/constants.js",
        "default": "./dist/constants.cjs"
    }
}

This exposes the module to users in multiple formats. import is used when a user uses an esm import for the entry point. default is used in any other case (i.e. a cjs require).

2. Add the file to the tsup build in the package.json config:

{
  "tsup": {
    "entryPoints": [
      "src/index.ts",
+     "src/constants.ts"
    ]
    "format": [
      "esm",
      "cjs"
    ],
    "dts": {
      "resolve": true
    },
    "splitting": true
  }
}

Note the options here. format specifies for the package to be bundled in both esm and cjs, which allows for a dual publish. dts.resolve is used to bundle types for devDependencies. For example, if you use a TypeScript utilities package, such as ts-essentials, the types will be bundled (in the .d.ts files) to avoid a dependency on ts-essentials. splitting enables an experimental feature that allows for creating chunks with cjs. This helps to avoid duplicating code with a package with multiple entry points.

The entryPoints (src/index.ts and src/constants.ts), specify the files that are our entry points, so when you add an entry point, it must also be added to the build config like before.