Webpack Changed Files Logger Plugin

ChangedFilesPlugin.js

const fs = require("fs");

const filepath = "craco-changed-files.json";

/**
 * This overwrites a log file of file changes that caused a rebuild.
 */
class ChangedFilesLogPlugin {
  constructor() {
    fs.writeFileSync(filepath, JSON.stringify([], null, 2), "utf8");
  }
  apply(compiler) {
    compiler.hooks.watchRun.tap("WatchRun", (compiler) => {
      if (compiler?.watchFileSystem?.watcher?.mtimes) {
        const changedTimes = compiler.watchFileSystem.watcher.mtimes;
        const changedFiles = Object.keys(changedTimes);

        if (changedFiles.length) {
          const logData = JSON.parse(fs.readFileSync(filepath, "utf8"));
          logData.push(changedFiles);
          fs.writeFileSync(filepath, JSON.stringify(logData, null, 2), "utf8");
        }
      }
    });
  }
}