unplugin-define

Replace variables in code with other values or expressions. Supports Vite, Rollup, Webpack, Rspack and more.

NOTE

The original intention of this plugin is to provide compatibility for lower-level plugins. You should give priority to using the define that comes with the build tool.
such as:
Vite define

Install

npm i unplugin-define

See example: example/

Usage

UnpluginDefine([
  {
  // include: [],
  // exclude: [],
    replacements: {
      'process.env.NODE_ENV': '\'development\'',
      'API_PREFIX': '/api',
      'TRUE': true,
      'TRUE_STRING': 'true',
      'UNDEFINED': undefined,
      'UNDEFINED_STRING': 'undefined',
    }
  },
// ...
])

// input
if (process.env.NODE_ENV === 'development')
  console.log('run in development mode')

fetch('API_PREFIX/test')

console.log(TRUE === TRUE_STRING)
console.log(UNDEFINED === UNDEFINED_STRING)

// output
if ('development' === 'development')
  console.log('run in development mode')

fetch('/api/test')

console.log(true === true)
console.log(undefined === undefined)

Vite

// vite.config.ts
import UnpluginDefine from 'unplugin-define/vite'

export default defineConfig({
  plugins: [
    UnpluginDefine({
      // ...
    }),
  ],
})

Rollup

// rollup.config.js
import UnpluginDefine from 'unplugin-define/rollup'

export default {
  plugins: [
    UnpluginDefine({
      // ...
    }),
  ],
}

Webpack

// webpack.config.js
const UnpluginDefine = require('unplugin-define/webpack')

module.exports = {
  plugins: [
    UnpluginDefine({
      // ...
    }),
  ]
}

Nuxt

// nuxt.config.js
export default {
  buildModules: [
    ['unplugin-define/nuxt', {
      // ...
    }],
  ],
}

This module works for both Nuxt 2 and Nuxt Vite

Vue CLI

// vue.config.js
const UnpluginDefine = require('unplugin-define/webpack')

module.exports = {
  configureWebpack: {
    plugins: [
      UnpluginDefine({
        // ...
      }),
    ],
  },
}

esbuild

// esbuild.config.js
import { build } from 'esbuild'
import UnpluginDefine from 'unplugin-define/esbuild'

build({
  plugins: [
    UnpluginDefine({
      // ...
    }),
  ],
})

Rspack

// rspack.config.js
const UnpluginDefine = require('unplugin-define/rspack')

module.exports = defineConfig({
  plugins: [
    UnpluginDefine({
      // ...
    }),
  ]
})