Function watchFiles

lib/internal/test_runner/runner.js:603–695

(testFiles, opts)

}

function watchFiles(testFiles, opts) {
  const runningProcesses = new SafeMap();
  const runningSubtests = new SafeMap();
  const watcherMode = opts.hasFiles ? 'filter' : 'all';
  const watcher = new FilesWatcher({ __proto__: null, debounce: 200, mode: watcherMode, signal: opts.signal });
  if (!opts.hasFiles) {
    watcher.watchPath(opts.cwd);
  }
  const filesWatcher = { __proto__: null, watcher, runningProcesses, runningSubtests };
  opts.root.harness.watching = true;

  async function restartTestFile(file) {
    const runningProcess = runningProcesses.get(file);
    if (runningProcess) {
      runningProcess.kill();
      await once(runningProcess, 'exit');
    }
    if (!runningSubtests.size) {
      // Reset the topLevel counter
      opts.root.harness.counters.topLevel = 0;
    }

    await runningSubtests.get(file);
    runningSubtests.set(file, runTestFile(file, filesWatcher, opts));
  }

  // Watch for changes in current filtered files
  const onChanged = ({ owners, eventType }) => {
    if (!opts.hasFiles && (eventType === 'rename' || eventType === 'change')) {
      const updatedTestFiles = createTestFileList(opts.globPatterns, opts.cwd);
      const newFileName = ArrayPrototypeFind(updatedTestFiles, (x) => !ArrayPrototypeIncludes(testFiles, x));
      const previousFileName = ArrayPrototypeFind(testFiles, (x) => !ArrayPrototypeIncludes(updatedTestFiles, x));

      testFiles = updatedTestFiles;

      // When file renamed (created / deleted) we need to update the watcher
      if (newFileName) {
        owners = new SafeSet().add(newFileName);
        const resolveFileName = isAbsolute(newFileName) ? newFileName : resolve(opts.cwd, newFileName);
        watcher.filterFile(resolveFileName, owners);
      }

      if (!newFileName && previousFileName) {
        return; // Avoid rerunning files when file deleted
      }
    }
    // Reset the root start time to recalculate the duration
    // of the run
    opts.root.clearExecutionTime();
    opts.root.reporter[kEmitMessage]('test:watch:restarted');

    // Restart test files
    if (opts.isolation === 'none') {
      PromisePrototypeThen(restartTestFile(kIsolatedProcessName), undefined, (error) => {
        triggerUncaughtException(error, true /* fromPromise */);
      });
    } else {
      watcher.unfilterFilesOwnedBy(owners);