Sync Gulp Tasks with run-sequence

By  on  

gulp.js is an awesome utility for so many things.  I've recently started using gulp as a build tool for the next blog redesign, whenever that may come.  In the past I had written my own build scripts but they quickly got messy and I ran into problems with concurrent tasks and knowing when each was complete.  gulp.js has made my build code prettier but I still get caught with timing issues due to async tasks.

Of course the nature of JS is becoming async but sometimes I just want a "top down" build process -- that's where run-sequence comes in.  With run-sequence I can easily group tasks to ensure they are done before setting off other tasks!

run-sequence works by passing arguments in the form of arrays or strings; an array signifies the tasks can be run concurrently, a string signifies a single task:

var runSequence = require('run-sequence');

gulp.task('some-task', function() {
	runSequence(
		['task-1', 'task-2', 'task-3'], // These 3 can be done in parallel
		'task-4', // ...then just do this
		['task-5', 'task-5'], // ...then do these things in parallel
		'task-6', // ...then do this
		// ....
	);
});

Each successive argument waits for the previous task(s) to finish.  My future theme's working gulp build file default task looks as follows:

// Create the default run action, which should be the entire build
gulp.task('default', function() {
	runSequence(
		['copy-js-dir', 'copy-php-files', 'copy-image-files', 'compile-stylus'],
		'clone-prism',
		['minify-css', 'minify-js'],
		'replace-build-ids',
		'create-backup-zip',
		'move-to-wordpress'
	);
});

JavaScript purists will hate on me for not creating my own promises to avoid the need for sync and run-sequence, but to be honest, I don't care.  Adding my own promises would make the code messier and with little speed benefit.

Sometimes we have to make concessions for the sake of maintainability -- all developers know that.  run-sequence was a concession I've made to keep my code maintainable and logical in my own head.

Recent Features

  • By
    CSS Animations Between Media Queries

    CSS animations are right up there with sliced bread. CSS animations are efficient because they can be hardware accelerated, they require no JavaScript overhead, and they are composed of very little CSS code. Quite often we add CSS transforms to elements via CSS during...

  • By
    JavaScript Promise API

    While synchronous code is easier to follow and debug, async is generally better for performance and flexibility. Why "hold up the show" when you can trigger numerous requests at once and then handle them when each is ready?  Promises are becoming a big part of the JavaScript world...

Incredible Demos

  • By
    HTML5 Input Types Alternative

    As you may know, HTML5 has introduced several new input types: number, date, color, range, etc. The question is: should you start using these controls or not? As much as I want to say "Yes", I think they are not yet ready for any real life...

  • By
    CSS Background Animations

    Background animations are an awesome touch when used correctly.  In the past, I used MooTools to animate a background position.  Luckily these days CSS animations are widely supported enough to rely on them to take over JavaScript-based animation tasks.  The following simple CSS snippet animates...

Discussion

  1. Pablo Perez

    Thanks for all your articles David!

  2. I recently came across Gulp and encountered the same issues… and found the same solution, before Gulp 4 is released !

    with run-sequence, I can even load/queue my tasks as modules and share them across different projects.

  3. Juha

    I’d add callback in tasks, at least for the sake of example – otherwise tasks depending on it would not wait until it is completed, right?

    gulp.task('some-task', function(done) {
      runSequence('task-1', ['task-2', 'task-3'], done);
    }
    
  4. Damn, that’s awesome! I remember seeing this module a while back and not thinking much of it, but the feature you demonstrate where you can define subtasks to run in parallel is very impressive.

    Took two minutes to setup, works like a charm. Thanks for sharing :)

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!