HardSourceWebpackPlugin

0.13.1 verified Sat Apr 25 auth: no javascript deprecated

HardSourceWebpackPlugin is a webpack plugin that provides intermediate caching of module compilation results to disk, drastically speeding up subsequent builds (second build is significantly faster). Version 0.13.1 is the latest stable release, last updated in 2020. It works by caching the output of webpack's module resolution and transformation steps, using a configurable cache directory and hash-based invalidation. Key differentiators: it caches at the module level (not just the entire bundle), supports parallel builds via ParallelModulePlugin, and allows excluding specific modules. However, it is no longer maintained and may have compatibility issues with modern webpack versions (5+), making it less suitable for new projects compared to persistent caching built into webpack 5.

Common errors

error Module not found: Error: Can't resolve 'hard-source-webpack-plugin' ↓

cause Package not installed or mistaken import path.

fix

Run npm install --save-dev hard-source-webpack-plugin and ensure the require path is correct.

error Error: HardSourceWebpackPlugin is not a constructor ↓

cause Using ES6 import instead of CommonJS require.

fix

Change import HardSourceWebpackPlugin from ... to const HardSourceWebpackPlugin = require('hard-source-webpack-plugin');

error TypeError: Cannot read property 'tap' of undefined ↓

cause Incompatible version of webpack; HardSourceWebpackPlugin may call hooks not present in webpack 5.

fix

Downgrade webpack to version 4, or migrate to webpack 5 persistent cache.

error Build fails silently with no errors after first build (assets not emitted) ↓

cause Known issue with mini-css-extract-plugin where assets are not emitted on repeated builds.

fix

Add ExcludeModulePlugin to exclude mini-css-extract-loader paths. Example: new HardSourceWebpackPlugin.ExcludeModulePlugin([{ test: /mini-css-extract-plugin[\\/]dist[\\/]loader/ }])

Warnings

deprecated Package is no longer maintained (last release 2020) and may not work with webpack 5+. ↓

fix Use webpack 5's built-in persistent caching (cache: { type: 'filesystem' }) instead. For webpack 4, consider using babel-loader's cacheDirectory or other caching strategies.

breaking HardSourceWebpackPlugin may cause memory leaks or build failures with certain loaders, especially mini-css-extract-plugin. ↓

fix Use ExcludeModulePlugin to exclude problematic loaders, or switch to webpack 5 persistent cache.

gotcha First build is not cached; only subsequent builds benefit. Cache must be manually cleared if build configuration changes unexpectedly. ↓

fix Delete the cache directory or use the configHash and environmentHash options to ensure cache invalidation.

gotcha The package does not support ES module imports (import). Only CommonJS require() works. ↓

fix Use const HardSourceWebpackPlugin = require('hard-source-webpack-plugin');

gotcha ParallelModulePlugin is experimental and may cause issues with webpack-dev-server or hot module replacement. ↓

fix Avoid using ParallelModulePlugin with dev server; consider using webpack's built-in parallelism (webpack 5) or thread-loader.

Install

npm install hard-source-webpack-plugin

yarn add hard-source-webpack-plugin

pnpm add hard-source-webpack-plugin

Imports

HardSourceWebpackPlugin

wrong

import HardSourceWebpackPlugin from 'hard-source-webpack-plugin'; // ESM not supported

correct

const HardSourceWebpackPlugin = require('hard-source-webpack-plugin');

The package only supports CommonJS (require). Using ES6 import will fail.

HardSourceWebpackPlugin.ExcludeModulePlugin
wrong
```
import { ExcludeModulePlugin } from 'hard-source-webpack-plugin'; // ESM not supported
```
correct
```
const { ExcludeModulePlugin } = require('hard-source-webpack-plugin');
```
ExcludeModulePlugin is a static property on HardSourceWebpackPlugin; destructure require or access via HardSourceWebpackPlugin.ExcludeModulePlugin.

HardSourceWebpackPlugin.ParallelModulePlugin

wrong

const ParallelModulePlugin = require('hard-source-webpack-plugin/parallel'); // wrong path

correct

const { ParallelModulePlugin } = require('hard-source-webpack-plugin');

ParallelModulePlugin is available as a static property of the main export, not as a separate module.

Quickstart

Shows basic webpack configuration with HardSourceWebpackPlugin for caching modules to disk.

// webpack.config.js
const HardSourceWebpackPlugin = require('hard-source-webpack-plugin');

module.exports = {
  entry: './src/index.js',
  output: { filename: 'bundle.js', path: __dirname + '/dist' },
  plugins: [
    new HardSourceWebpackPlugin({
      cacheDirectory: 'node_modules/.cache/hard-source/[confighash]',
      info: { mode: 'none', level: 'warn' },
    }),
  ],
};