@teages/nuxt-legacy

A Nuxt module for supporting legacy browsers.

• ✨  Release Notes

Setup

Install the module to your Nuxt application with one command:

# vite
pnpm add @teages/nuxt-legacy @vitejs/plugin-legacy

Then configure it in your nuxt.config.ts:

// nuxt.config.ts
export default defineNuxtConfig({
  modules: [
    '@teages/nuxt-legacy'
  ],

  legacy: {
    vite: {}, // `@vitejs/plugin-legacy` options
  },
})

maximum compatibility (not recommended)

// nuxt.config.ts
export default defineNuxtConfig({
  modules: [
    '@teages/nuxt-legacy'
  ],

  legacy: {
    vite: {
      targets: ['fully supports proxy'],
      modernPolyfills: true,
    },
  },

  vite: {
    build: {
      // required on plugin-legacy 8.1+ to support Chrome <80
      minify: 'terser',
    },
  },
})

Compatibility

Nuxt & @vitejs/plugin-legacy

On Nuxt 3 or Nuxt 4.0.3–4.4? Stay on the last compatible release:

• Nuxt 3 → @teages/nuxt-legacy@2.0.2 with @vitejs/plugin-legacy@^7
• Nuxt 4.0.3–4.4 → @teages/nuxt-legacy@2.0.2 with @vitejs/plugin-legacy@^7

@teages/nuxt-legacy@3 requires Nuxt >=4.5.0 (which ships Vite 8) and @vitejs/plugin-legacy@^8.0.0.

@teages/nuxt-legacy@3 is compatible with Nuxt >=4.5.0. It also has experimental support for Nuxt 5 nightly versions.

Use @vitejs/plugin-legacy@^8.0.0 (Vite 8 ships with both Nuxt 4.5+ and Nuxt 5).

Compatibility with later Nuxt versions is not guaranteed until those versions have been tested and added to the matrix below.

Check the results for current module version:

The test result runs with custom AbortController polyfill, which is not included in this module and you need to add it by yourself, see Custom Polyfills.

Nuxt Version	@vitejs/plugin-legacy	Chrome 49	Chrome 61	Chrome 104	Chrome 105	Latest Chrome
4.5.x	8.x	✅ (with minify: 'terser')	✅ (with minify: 'terser')	✅ legacy	✅ modern	✅ modern

Browser support

The module is tested with the following browsers:

• Chrome 49: the oldest Chrome version with full Proxy support; exercises the non-ESM legacy path
• Chrome 61: supports ESM but not dynamic import; exercises the ESM fallback path
• Chrome 104: the last version before import.meta.resolve; exercises the plugin-legacy v8 fallback boundary
• Chrome 105: the first modern Chrome target in plugin-legacy v8; exercises modern chunks and the Array.prototype.toSorted polyfill
• Latest Chrome: regression guard for current browsers

You can test by yourself by visiting the playground with your target browsers.

Content Security Policy

It injects some inline scripts to fix legacy browser compatibility. The hashes keep sync with the latest version of @vitejs/plugin-legacy, the current value is:

• sha256-MS6/3FCg4WjP9gwgaBGwLpRCY6fZBgwmhVCdrPrNf3E=
• sha256-tQjf8gvb2ROOMapIxFvFAYBeUJ0v1HCbOcSmDNXGtDo=
• sha256-w36slEqa9euNKxfvkw+LLGsDIr++3rsZXpZxtmRh8Aw=
• sha256-+5XkZFazzJo8n0iOP4ti/cLCMUudTf//Mzkb7xNPXIc=

cspHashes is also available in the module:

import { cspHashes } from '@teages/nuxt-legacy'

Custom Polyfills

The module supports custom polyfills to provide additional compatibility for legacy browsers.

This allows you to add polyfills for specific APIs that may not be covered by the Vite legacy plugin (it uses babel and core-js).

Since Nuxt 4.2, you need to add AbortController polyfill because it will be used in useFetch and useAsyncData and its polyfill is not included in core-js.

Configuration

You can customize the polyfill behavior in your nuxt.config.ts:

export default defineNuxtConfig({
  modules: ['@teages/nuxt-legacy'],

  legacy: {
    vite: {
      targets: ['fully supports proxy'],
    },

    // Custom polyfills configuration
    customPolyfills: {
      // Specify custom scan directories
      scanDirs: ['polyfills', 'other-polyfills'],

      // Or manually specify polyfill files
      polyfills: [
        './compat/event-target.ts',
        './compat/abort-controller.ts'
      ]
    }
  }
})

Writing Polyfills

Polyfill is a script that runs before your application code.

Here's an example:

// polyfills/event-target.ts
import { EventTarget } from 'event-target-shim'

setup(window)

function setup(self: typeof window) {
  // Check if polyfill is needed
  let isPolyfillNeeded = false
  try {
    // eslint-disable-next-line no-new
    new self.EventTarget()
  }
  catch {
    isPolyfillNeeded = true
  }

  if (!isPolyfillNeeded) {
    return
  }

  // Apply polyfill
  Object.assign(self, { EventTarget })
}

Credits

• IlyaSemenov/nuxt-vite-legacy: module by @IlyaSemenov with his idea

• BrowserStack. This project is tested with BrowserStack.

Contribution

Local development

# Enable Corepack and install dependencies
corepack enable
pnpm install

# Generate type stubs
pnpm dev:prepare

# Develop with the playground
pnpm dev

# Build the playground
pnpm dev:build

# Run ESLint
pnpm lint

# Run Vitest
pnpm test
pnpm test:watch

# Run type checks
pnpm test:types

Releases are managed by the automated workflow in .github/workflows/release.yml.