CoreJS Upgrade Webpack Plugin

4.0.1 verified Sat Apr 25 auth: no javascript maintenance

A webpack plugin that transforms core-js v2 require/module paths to core-js v3 counterparts during bundling. Current stable version is 4.0.1 with maintenance-level releases. It resolves mismatched core-js versions by mapping old path patterns to new ones, preventing bundle bloat and runtime errors from library dependencies. Supports custom resolve directories via resolveFrom option. Released intermittently; uses core-js's path mapping to ensure the latest core-js is used everywhere. Differentiator: automates migration in existing webpack setups without manual code changes.

Common errors

error Cannot find module 'corejs-upgrade-webpack-plugin' ↓

cause Attempting to require the plugin via CommonJS require.

fix

Use ESM import statement or use .mjs extension.

error TypeError: CoreJSUpgradeWebpackPlugin is not a constructor ↓

cause Wrong import style, e.g., using default import when plugin is exported as named.

fix

Use import CoreJSUpgradeWebpackPlugin from 'corejs-upgrade-webpack-plugin' (ESM) or const { CoreJSUpgradeWebpackPlugin } = require('...') (CJS).

Warnings

breaking Version 3.0.0 changed options structure; resolveFrom now expects an array. ↓

fix Update resolveFrom to an array: new CoreJSUpgradeWebpackPlugin({ resolveFrom: [path] })

deprecated The plugin is in maintenance mode; no new features planned. ↓

fix Consider using built-in webpack resolve.alias for core-js if applicable.

gotcha Plugin only transforms paths that match /core-js/; nested references may be missed. ↓

fix Manually audit dependencies if multiple core-js versions remain.

Install

npm install corejs-upgrade-webpack-plugin

yarn add corejs-upgrade-webpack-plugin

pnpm add corejs-upgrade-webpack-plugin

Imports

CoreJSUpgradeWebpackPlugin

wrong

const CoreJSUpgradeWebpackPlugin = require('corejs-upgrade-webpack-plugin')

correct

import CoreJSUpgradeWebpackPlugin from 'corejs-upgrade-webpack-plugin'

ESM-only; default import. CommonJS require will fail.

CoreJSUpgradeWebpackPlugin

wrong

const CoreJSUpgradeWebpackPlugin = require('corejs-upgrade-webpack-plugin').default

correct

const { CoreJSUpgradeWebpackPlugin } = require('corejs-upgrade-webpack-plugin')

For CommonJS, use named destructuring. Default export is not available.

Options

import type { Options } from 'corejs-upgrade-webpack-plugin'

Use type import for TypeScript, not value import.

Quickstart

Demonstrates ESM import and plugin instantiation with optional resolveFrom option for custom core-js resolution path.

// webpack.config.js
import CoreJSUpgradeWebpackPlugin from 'corejs-upgrade-webpack-plugin';

export default {
  plugins: [
    new CoreJSUpgradeWebpackPlugin({
      resolveFrom: [process.cwd()],
    }),
  ],
};