webpack-deadcode-plugin/src/index.js

const path = require("path");
const detectDeadcode = require("./detect");

class WebpackDeadcodePlugin {
  constructor(options = {}) {
    this.options = options;
  }

  apply(compiler) {
    const options = Object.assign(
      {
        patterns: ["**/*.*"],
        exclude: [],
        context: compiler.context,
        failOnHint: false,
        detectUnusedFiles: true,
        detectUnusedExport: true,
        log: "all",
      },
      this.options
    );

    if (compiler.hooks) {
      compiler.hooks.afterEmit.tapAsync("WebpackDeadcodePlugin", this.handleAfterEmit.bind(this, options));
    } else {
      compiler.plugin(`after-emit`, this.handleAfterEmit.bind(this, options));
    }
  }

  handleAfterEmit(options, compilation, callback) {
    detectDeadcode(compilation, options);
    callback();
  }
}

module.exports = WebpackDeadcodePlugin;