Webpack Deep Scope Analysis Plugin

1.7.0 verified Sat Apr 25 auth: no javascript maintenance

Webpack plugin (npm package deep-scope-analyser v1.7.0, low activity) that improves tree-shaking by performing deep scope analysis to eliminate unused imports and exports. Designed for webpack 4.14.0+ and Node.js 8+. It solves webpack issue #6264 by analyzing variable scopes to determine which imports can be safely removed, beyond what webpack's built-in tree-shaking achieves. The plugin works only with ES module syntax (import/export) and requires the PURE annotation for side-effect marking. Originally named webpack-deep-scope-plugin (v1.5.x), renamed to deep-scope-analyser in v1.6.0 for standalone use. Maintained by a GSoC 2018 student, but has seen no updates since 2019. Differentiators: deeper analysis than standard tree-shaking; but limited to webpack 4 and ESM-only, with potential compatibility issues.

Common errors

error Module not found: Error: Can't resolve 'webpack-deep-scope-plugin' ↓

cause Package was renamed to deep-scope-analyser in v1.6.0.

fix

npm install deep-scope-analyser (or pin version to 1.5.4) and update import to deep-scope-analyser.

error TypeError: webpackDeepScopeAnalysisPlugin is not a constructor ↓

cause Using CommonJS require without .default property.

fix

const WebpackDeepScopeAnalysisPlugin = require('webpack-deep-scope-plugin').default;

error Error: Cannot find module 'webpack' ↓

cause Missing webpack peer dependency.

fix

npm install webpack@4 --save-dev

Warnings

breaking Renamed from webpack-deep-scope-plugin (v1.5.x) to deep-scope-analyser (v1.6.0). Existing import paths break. ↓

fix Use package deep-scope-analyser or continue using webpack-deep-scope-plugin (v1.5.4) for older webpack.

deprecated Package has not been updated since 2019; may be incompatible with webpack 5 and modern Node.js (>=14). ↓

fix Consider alternatives like webpack's built-in sideEffects flag or optimization.usedExports for webpack 5+.

gotcha The plugin only works with ES module syntax (import/export). If Babel or TypeScript transpile to CommonJS (require/module.exports), the analysis fails silently. ↓

fix Ensure your code uses native ES modules; avoid using @babel/plugin-transform-modules-commonjs.

gotcha CommonJS require('webpack-deep-scope-plugin') returns an empty object; must use .default property. ↓

fix Use const Plugin = require('webpack-deep-scope-plugin').default;

Install

npm install deep-scope-analyser

yarn add deep-scope-analyser

pnpm add deep-scope-analyser

Imports

default

wrong

import { WebpackDeepScopeAnalysisPlugin } from 'webpack-deep-scope-plugin';

correct

import WebpackDeepScopeAnalysisPlugin from 'webpack-deep-scope-plugin';

Default export; the package ships TypeScript definitions.

default

wrong

const WebpackDeepScopeAnalysisPlugin = require('webpack-deep-scope-plugin');

correct

const WebpackDeepScopeAnalysisPlugin = require('webpack-deep-scope-plugin').default;

CommonJS require must explicitly access .default because the package uses ESM-style default export.

default

wrong

import { default as WebpackDeepScopeAnalysisPlugin } from 'deep-scope-analyser';

correct

import WebpackDeepScopeAnalysisPlugin from 'deep-scope-analyser';

Alternative package name deep-scope-analyser also works; same default import pattern.

Quickstart

Adds deep scope analysis plugin to a webpack 4 production config to improve tree-shaking.

// webpack.config.js
const WebpackDeepScopeAnalysisPlugin = require('webpack-deep-scope-plugin').default;

module.exports = {
  mode: 'production',
  entry: './src/index.js',
  output: {
    path: __dirname + '/dist',
    filename: 'bundle.js'
  },
  plugins: [
    new WebpackDeepScopeAnalysisPlugin()
  ]
};