@downlevel/unconfig

unconfig

A universal solution for loading configurations.

Why?

Configuration is hard, especially when you want to build an ecosystem of your tools.

You want your tools to be general and easy to use, you allow you config to be defined in a custom field of package.json.

You want your tools to be easy to integrate, you allow the configs to be defined in other tools' configurations like vite.config.js or webpack.config.js.

You want the configs to be agnostic and probably need to be load by IDE, you create new config files like .myconfigrc.

You want the configs to also be flexible and dynamic, you make your config files a JavaScript file, like my.config.js.

Then you want users to be able to use ESM and TypeScript, you also make your config accepting .ts or .mjs.

So users' project root end up with a lot of config files like .npmrc, rollup.config.js, .eslintrc, tsconfig.json, jest.config.js, postcss.config.js, nuxt.config.js, vite.config.cjs, windi.config.ts, etc. And each of them use different syntax, in JSON, in CJS, in ESM, in TypeScript, in INI, in TOML...

unconfig can't solve this fragmentation entirely, but it's trying to make loading them easier for tool authors.

Usage

npm i unconfig

For example, to load config for my.config:

import { loadConfig } from 'unconfig'

const { config, filepath } = await loadConfig({
  sources: [
    // load from `unocss.config.xx`
    {
      files: 'my.config',
      // default extensions
      extensions: ['ts', 'mts', 'cts', 'js', 'mjs', 'cjs', 'json', ''],
    },
    // load `my` field in `package.json` if no above config files found
    {
      files: 'package.json',
      extensions: [],
      rewrite(config) {
        return config?.my
      },
    },
    // load inline config from `vite.config`
    {
      files: 'vite.config',
      async rewrite(config) {
        const config = await (typeof config === 'function' ? config() : config)
        return config?.my
      },
    },
    // ...
  ],
  // if false, the only the first matched will be loaded
  // if true, all matched will be loaded and deep merged
  merge: false
})

unconfig supports loading ts, mjs, js, json by default.

Sponsors

License

MIT License © 2021 Anthony Fu