Webpack - omit creation of LICENSE.txt files

Add extractComments: false to webpack.config.js

const TerserPlugin = require('terser-webpack-plugin');
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.
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module.exports = {
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.
.
  optimization: {
    minimizer: [new TerserPlugin({
      extractComments: false,
    })],
  },
.
.
.
};

To properly remove both the license file and the comments inside the bundle use:

optimization: {
  minimize: true,
  minimizer: [
    new TerserPlugin({
      extractComments: false,
      terserOptions: {
        format: {
          comments: false,
        },
      },
    }),
  ],
},

https://github.com/webpack-contrib/terser-webpack-plugin#remove-comments

The webpack documentation only has this https://webpack.js.org/plugins/terser-webpack-plugin/#extractcomments

extractComments: false

This helped me get rid of LICENSE.txt

Just add a simple custom plugin, Delete LICENSE.txt after building the file.

install remove library npm i rimraf

const rimraf = require('rimraf');

plugins: [
  new (class {
    apply(compiler) {
      compiler.hooks.done.tap('Remove LICENSE', () => {
        console.log('Remove LICENSE.txt');
        rimraf.sync('./dist/*.LICENSE.txt');
      });
    }
  })(),
]

For those who like me don't want to use the terser plugin, it's possible to remove all LICENSE.txt files, just adding to CleanWebpackPlugin options: cleanAfterEveryBuildPatterns: ['**/*.LICENSE.txt'], protectWebpackAssets: false. The downside of this approach is that .js vendor chunk files still have comments in the first line referring to the non-existent anymore licence license text files. To get rid also of these comments, I have created a customized plugin, which uses clean webpack plugin to remove txt files and also removes comments from vendor chunks:

const webpack = require('webpack');
const { CleanWebpackPlugin } = require('clean-webpack-plugin');

class CustomizedCleanWebpackPlugin {
  constructor({
    vendorJsFileRegex = /vendor.*\.js$/,
    licenseCommentRegex = /^\/\*\!.+\.LICENSE\.txt\s*\*\/\s*/,
    licenseTxtFilePattern = '**/*.LICENSE.txt',
    ...rest
  } = {}) {
    this.licenseCommentRegex = licenseCommentRegex;
    this.vendorJsFileRegex = vendorJsFileRegex;
    this.licenseTxtFilePattern = licenseTxtFilePattern;
    this.restCleanWebpackPlaginOptions = rest;
  }

  apply(compiler) {
    new CleanWebpackPlugin({
      cleanAfterEveryBuildPatterns: [this.licenseTxtFilePattern],
      protectWebpackAssets: false,
      ...this.restCleanWebpackPlaginOptions
    }).apply(compiler);

    compiler.hooks.compilation.tap('CustomizedCleanWebpackPlugin', (compilation) => {
      compilation.hooks.afterProcessAssets.tap(
        'CustomizedCleanWebpackPlugin',
        (assets) => {
          Object.entries(assets).forEach(([fileName, source]) => {
            if (fileName.match(this.vendorJsFileRegex)) {
              compilation.updateAsset(
                fileName,
                new webpack.sources.RawSource(
                  source.source().replace(this.licenseCommentRegex, '')
                )
              );
            }
          });
        }
      );
    });
  }
}

module.exports = { CustomizedCleanWebpackPlugin };

I solved it this way:

import TerserPlugin from "terser-webpack-plugin";
optimization: {
minimizer: [
  (compiler: Compiler): void => {
    new TerserPlugin({
      terserOptions: {
        format: {
          comments: false
        }
      },
      extractComments: false
    }).apply(compiler);
  }
]}

See: https://github.com/MarkZhuVUW/ts-react-s3-circleci-employer-tracker/blob/feature/service-worker-notification/webpack.prod.config.ts