source-map-loader

Install

npm i -D source-map-loader

Usage

Documentation: Using loaders

Example webpack config

module.exports = {
  module: {
    rules: [
      {
        test: /\.js$/,
        use: ["source-map-loader"],
        enforce: "pre"
      }
    ]
  }
};

This extracts SourceMaps from all js files (including node_modules). This is not very performant, so you may want to only apply the loader to relevant files.