問題描述

作為我正在編寫的一個小程序的一部分，我想使用 gulp 將大量文件轉(zhuǎn)換為 markdown.這不是獨立于程序的構(gòu)建步驟的一部分.這是程序的一部分.所以我沒有使用 gulpfile 來處理這個問題.

As part of a small program I'm writing, I would like to use gulp to convert a large set of a files to markdown. This is not part of a build step separate from the program. It's a part of the program. So I'm not using a gulpfile to handle this.

問題是，因為它是異步的，所以我想使用一個 Promise，它會在 gulp 任務(wù)完成時提醒我.

The problem is, since it's async, I want to use a promise which will alert me when the gulp task is finished.

這樣的東西是理想的:

io.convertSrc = function() {
  var def = q.defer();

  gulp.src(src + '/*.md')
    .pipe(marked({}))
    .pipe(gulp.dest(dist), function() {
      def.resolve('We are done!');
    });

    return def.promise;
}

但 pipe 不接受回調(diào).我怎么能處理這個?感謝您的幫助，我對 gulp 有點陌生.

But pipe doesn't take a callback. How could I handle this? Thanks for your help, I'm somewhat new to gulp.

推薦答案

gulp 中的一切都是一個流，所以你可以只監(jiān)聽 end 和 error 事件.

Everything in gulp is a stream, so you can just listen for the end and error events.

io.convertSrc = function() {
  var def = q.defer();
  gulp.src(src + '/*.md')
    .pipe(marked({}))
    .pipe(gulp.dest(dist))
    .on('end', function() {
      def.resolve();
    })
    .on('error', def.reject);
  return def.promise;
}

順便說一句，Q 1.0 不再被開發(fā)(除了一些修復(fù))并且將完全不兼容Q 2.0；我推薦 Bluebird 作為替代方案.

As an aside, Q 1.0 is no longer developed (aside from a few fixes here and there) and will be wholly incompatible with Q 2.0; I'd recommend Bluebird as an alternative.

還值得一提的是，NodeJS 0.12 及更高版本已內(nèi)置 ES6 承諾(不需要 --harmony 標(biāo)志)，因此如果您不尋求向后兼容性，您可以使用它們來代替..

Also worth mentioning that NodeJS 0.12 onwards has ES6 promises built into it (no --harmony flag necessary) so if you're not looking for backwards compatibility you can just use them instead..

io.convertSrc = function() {
  return new Promise(function(resolve, reject) {
    gulp.src(src + '/*.md')
      .pipe(marked({}))
      .pipe(gulp.dest(dist))
      .on('end', resolve)
      .on('error', reject);
  });
};

這篇關(guān)于我如何保證在我的應(yīng)用程序中一次性使用 gulp?的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網(wǎng)！