webpack5 > webpack.IgnorePlugin failure

Bug report

What is the current behavior?

In the process of learning Webpack 5

> webpack5-ignoreplugin@1.0.0 build
> webpack

asset main.js 628 KiB [emitted] (name: main) 1 related asset
runtime modules 1020 bytes 4 modules
modules by path ./node_modules/moment/dist/locale/*.js 407 KiB 135 modules
./src/index.js 300 bytes [built] [code generated]
./node_modules/moment/dist/moment.js 150 KiB [built] [code generated]
./node_modules/moment/dist/locale/ sync ^\.\/.*$ 3.21 KiB [optional] [built] [code generated]
webpack 5.38.1 compiled successfully in 1237 ms

Expectations for main.js <=170kb

If the current behavior is a bug, please provide the steps to reproduce.

// src/index.js

import moment from 'moment'
console.log(moment().format('MMMM Do YYYY, h:mm:ss a'));

// webpack.config.js

const path = require('path')
const webpack = require('webpack');

module.exports = {
  mode:'none',
  devtool:'source-map',
  context:process.cwd(),
  entry:'./src/index.js',
  output:{
    path: path.resolve(__dirname, 'dist'),
    filename: '[name].js',
  },
  resolve: {
    modules:['node_modules'],
    mainFields:['jsnext:main','main']
  },
  plugins:[
    new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/),
  ]
}

What is the expected behavior?

ignore

moment>dist>locale

Other relevant information: webpack version: ^5.38.1 Node.js version: v12.16.3 Operating System: mac 10.15.7 Additional tools:

[myNameIsDu]

Yes, feel free to send a PR with fix, just remove it from schema

Sorry, there are some problems mentioned above, should be increased

"required": [ "resourceRegExp"]
"required": [ "checkResource" ]

I will send a PR later

[jcamden]

Thanks @myNameIsDu . I was intentionally not escaping the periods, but I should have added a glob, and you’re right that my regex probably should include escaped periods to be more specific: (i.e. /.*\.test(\.).*(ts|tsx)$/ ) Here’s what I’m running:

const webpack = require('webpack');

module.exports = {
  future: {
    webpack5: true,
  },
  webpack: (config) => {
    config.plugins.push(
      new webpack.IgnorePlugin({
        resourceRegExp: /.*\.test(\.).*(ts|tsx)$/,
      })
    );
    return config;
  },
};

Seems to work with Webpack 4, but build fails with Webpack 5 enabled:

info  - Creating an optimized production build  
Failed to compile.

HookWebpackError: Cannot read property 'slice' of undefined


> Build error occurred
Error: > Build failed because of webpack errors
    at /home/.../next/dist/build/index.js:17:924
    at processTicksAndRejections (node:internal/process/task_queues:94:5)
    at runNextTicks (node:internal/process/task_queues:63:3)
    at processImmediate (node:internal/timers:437:9)
    at async Span.traceAsyncFn (/home/...trace.js:6:584)

I assume this means that the modified Webpack config didn’t add up to a proper array in some regard, but I’m not sure.