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When working in a large codebase it's likely someone else will add a new package or upgrade an existing package. This often leads to a convoluted webpack error or runtime error as a result of a missing or outdated package.

The intent of this plugin is to be run in development with webpack so as you checkout different branches or recent changes in version control this plugin can remind you when there are missing or outdated packages.

For example, say a webpack watch process is running and started on the master branch. In the process of working or reviewing code the branch add-underscore is checked out (git checkout add-underscore). In this case, the branch name gives it away but sometimes it's not immediately obvious that a package was added or changed. This plugin will list the differences between the installed versus expected packages. In this specific example, the forceKill option is enabled so the webpack process also exits.

Demo of yarn-check-webpack-plugin

Getting Started

Install the package:

yarn add -D yarn-check-webpack-plugin
npm install --save-dev yarn-check-webpack-plugin

And add the plugin to webpack.config.js:

const { YarnCheck } = require("yarn-check-webpack-plugin");

module.exports = {
  // Additional configuration...
  plugins: [new YarnCheck()]

Or, to webpack.config.ts:

import * as webpack from "webpack";
import { YarnCheck } from "yarn-check-webpack-plugin";

const config: webpack.Configuration = {
  // Additional configuration...
  plugins: [new YarnCheck()]

module.exports = config;

Then, run webpack as normal.

How do I verify it's working?

Find a random node_module (eg: ls node_modules) and remove it (eg: rm -rf node_modules/lodash) and trigger a rebuild (by changing a file if in watch mode) or by running webpack again.

The output should include something that looks like:

Missing packages:
  - lodash
Please run `yarn install --check-files` to update.


All configuration is optional. Pass a configuration object when initializing to change any of the options.

For example:

new YarnCheck({
  rootDirectory: "./another/directory",
  exclude: /underscore/,
  forceKill: true


Type: String

Description: The root directory to run the commands. This should be the directory that contains package.json, yarn.lock and node_modules. By default, it will run in the current directory. This option only needs to be set if this plugin is being run in a different directory.


Type: RegExp

Description: Ignore warnings for any missing or wrong version packages that match this regex expression.


Type: Boolean

Description: Force the webpack process to exit if there is an error. This is desirable if you want to ensure the proper packages are installed before continuing.

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