javascript - 使用 grunt-contrib-watch 深度单向同步两个目录。代码有效，但 grunt-contrib-watch 重新初始化时间太慢

Question

我有两个目录 src 和 compiled。我想使用 Grunt Watch 确保从 src 到 compiled 的单向数据同步.作为中间步骤，我想编译 *.less 文件以及使用 ES6 语法编写的 *.js 文件的子集。

我已经成功编写了满足我需要的任务:

// NOTE: Spawn must be disabled to keep watch running under same context in order to dynamically modify config file.
watch: {
  // Compile LESS files to 'compiled' directory.
  less: {
    options: {
      interrupt: true,
      spawn: false,
      cwd: 'src/less'
    },
    files: ['**/*.less'],
    tasks: ['less']
  },
  // Copy all non-ES6/LESS files to 'compiled' directory. Include main files because they're not ES6. Exclude LESS because they're compiled.
  copyUncompiled: {
    options: {
      event: ['added', 'changed'],
      spawn: false,
      cwd: 'src'
    },
    files: ['**/*', '!**/background/**', '!**/common/**', '!contentScript/youTubePlayer/**/*', '!**/foreground/**', '!**/test/**', '!**/less/**', '**/main.js'],
    tasks: ['copy:compileSingle']
  },
  // Compile and copy ES6 files to 'compiled' directory. Exclude main files because they're not ES6.
  copyCompiled: {
    options: {
      event: ['added', 'changed'],
      spawn: false,
      cwd: 'src/js'
    },
    files: ['background/**/*', 'common/**/*', 'contentScript/youTubePlayer/**/*', 'foreground/**/*', 'test/**/*', '!**/main.js'],
    tasks: ['babel:compileSingle']
  },
  // Whenever a file is deleted from 'src' ensure it is also deleted from 'compiled'
  remove: {
    options: {
      event: ['deleted'],
      spawn: false,
      cwd: 'src'
    },
    files: ['**/*'],
    tasks: ['clean:compiledFile']
  }
}

  grunt.event.on('watch', function(action, filepath, target) {
    // Determine which task config to modify based on the event action.
    var taskTarget = '';
    if (action === 'deleted') {
      taskTarget = 'clean.compiledFile';
    } else if (action === 'changed' || action === 'added') {
      if (target === 'copyCompiled') {
        taskTarget = 'babel.compileSingle';
      } else if (target === 'copyUncompiled') {
        taskTarget = 'copy.compileSingle';
      }
    }

    if (taskTarget === '') {
      console.error('Unable to determine taskTarget for: ', action, filepath, target);
    } else {
      // Drop src off of filepath to properly rely on 'cwd' task configuration.
      grunt.config(taskTarget + '.src', filepath.replace('src\\', ''));
    }
  });

这些任务监视相应的文件。事件处理程序动态修改 clean copy 和 babel 任务，以便它们处理正在添加/更改/删除的文件。

但是，我正在观看数千个文件并且监视任务需要花费大量时间来初始化。在我的高端开发 PC 上初始化需要 6 秒以上。监视任务在每个任务后重新初始化这一事实加剧了这个问题。

这意味着如果我有两个文件，fileA 和 fileB，并且我修改了 fileA 并保存，那么会有 6+ 秒watch 未能检测到对 fileB 的修改的时间段。这导致我的两个目录之间不同步。

我发现了这个关于我的问题的 GitHub 问题，但它仍然未解决且未得到答复:https://github.com/gruntjs/grunt-contrib-watch/issues/443

GitHub 上的讨论强调该问题可能仅在设置了 spawn: false 时出现，但是，根据 Grunt Watch documentation :

If you need to dynamically modify your config, the spawn option must be disabled to keep the watch running under the same context.

因此，我认为我需要继续使用 spawn: false。

我不得不假设这是 Grunt 任务的一个非常标准的过程。我在这里遗漏了一些明显的东西吗？ Watch 任务不适合这个目的吗？其他选择？

Answer 1

好吧，我有一个可行的解决方案，但它不很漂亮。

我确实最终使用了 grunt-newer协助解决问题。不幸的是，它不能很好地与 grunt-contrib-copy 配合使用，因为复制文件不会更新其最后修改时间，因此 grunt-newer 将在 100% 的时间内执行。

因此，我 fork 了 grunt-contrib-copy 并添加了一个选项以允许更新上次修改时间:https://github.com/MeoMix/grunt-contrib-copy

有了它，我现在可以写:

// NOTE: Spawn must be disabled to keep watch running under same context in order to dynamically modify config file.
watch: {
  // Compile LESS files to 'compiled' directory.
  less: {
    options: {
      interrupt: true,
      cwd: 'src/less'
    },
    files: ['**/*.less'],
    tasks: ['less']
  },
  // Copy all non-ES6/LESS files to 'compiled' directory. Include main files because they're not ES6. Exclude LESS because they're compiled.
  copyUncompiled: {
    options: {
      event: ['added', 'changed'],
      cwd: 'src'
    },
    files: ['**/*', '!**/background/**', '!**/common/**', '!contentScript/youTubePlayer/**/*', '!**/foreground/**', '!**/test/**', '!**/less/**', '**/main.js'],
    tasks: ['newer:copy:compiled']
  },
  // Compile and copy ES6 files to 'compiled' directory. Exclude main files because they're not ES6.
  copyCompiled: {
    options: {
      event: ['added', 'changed'],
      cwd: 'src/js'
    },
    files: ['background/**/*', 'common/**/*', 'contentScript/youTubePlayer/**/*', 'foreground/**/*', 'test/**/*', '!**/main.js'],
    tasks: ['newer:babel:compiled']
  },
  // Whenever a file is deleted from 'src' ensure it is also deleted from 'compiled'
  remove: {
    options: {
      event: ['deleted'],
      spawn: false,
      cwd: 'src'
    },
    files: ['**/*'],
    tasks: ['clean:compiledFile']
  }
}

grunt.event.on('watch', function(action, filepath) {
  if (action === 'deleted') {
    // Drop src off of filepath to properly rely on 'cwd' task configuration.
    grunt.config('clean.compiledFile.src', filepath.replace('src\\', ''));
  }
});

现在，只有当“src”比“dest”更新时，才会复制 ES6 文件以及非 LESS/非 ES6 文件。

不幸的是，当从“src”中删除时，grunt-newer 并不真正支持同步删除操作。因此，我继续使用我以前的代码进行“删除”操作。这仍然存在相同的缺陷，在删除发生后，监视任务将暂时失效。