Registry / is-webpack-bundle

is-webpack-bundle

library1.0.0jsnpmunverified

A micro-package (v1.0.0, no active releases since 2019) that detects at runtime whether the current module was bundled by webpack. It works by checking for the presence of a `__webpack_require__` function in the global scope. This is a simple, single-purpose utility with no dependencies. For similar detection in other bundlers (e.g., Rollup, Parcel), alternative approaches are needed. The package is published as a CommonJS module only, with no TypeScript type definitions.

npm install is-webpack-bundle

github ↗package ↗

INSTALL

IMPORT

SIG · IS-WEBPACK-BUNDLE

is-webpack-bundle

javascriptv1.0.0

Install

—

Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

default

✓ const isWebpackBundle = require('is-webpack-bundle');

✗ import isWebpackBundle from 'is-webpack-bundle';

Package is CommonJS-only; ESM import will fail in Node or bundlers expecting ESM.

default (ESM)

✓ import isWebpackBundle from 'is-webpack-bundle';

✗ const isWebpackBundle = require('is-webpack-bundle');

If your project is ESM, this import works in Node 12+ with `--experimental-require` or with bundlers like webpack, but the package itself is CJS. Prefer require for clarity.

default (TypeScript)

✓ // @ts-ignore or declare module const isWebpackBundle = require('is-webpack-bundle');

✗ import isWebpackBundle from 'is-webpack-bundle';

No type definitions exist. Use require with a type assertion or disable strict module checks.

Shows how to check if code is webpack-bundled and conditionally handle logic.

Debug

Known issues

gotchaThe check relies on a global `__webpack_require__` which may be absent in certain webpack configurations (e.g., output.libraryTarget: 'var') or minified bundles.

fix

Verify the check works in your specific webpack setup; consider alternative detection methods.

affects: >=1.0.0

gotchaIf the code is bundled with another bundler (e.g., Rollup, Parcel), the check will incorrectly return false even if inside a bundle.

fix

Use a bundler-agnostic detection library or check for other globals.

affects: >=1.0.0

gotchaThe module is CommonJS-only; importing via ESM may cause issues in strict ESM environments.

fix

Use require() or configure your bundler to handle CJS interop.

affects: >=1.0.0

Errors

Common errors & fixes

Cannot find module 'is-webpack-bundle'

Package not installed or typo in package name.

fix

Run npm install is-webpack-bundle

Uncaught ReferenceError: __webpack_require__ is not defined

The package's global check fails because __webpack_require__ is not exposed (e.g., in Node.js environment without webpack).

fix

This error should not happen because the package catches the ReferenceError internally; if it does, ensure you are not modifying global scope or using eval.

SyntaxError: Cannot use import statement outside a module

Trying to ESM-import the package without proper module configuration.

fix

Use require() or set "type": "module" in package.json and ensure the import path is valid.

Upgrade

Version history

1.0.0latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/thejameskyle/is-webpack-bundle ↗

packagehttps://www.npmjs.com/package/is-webpack-bundle ↗