Using Gulp

To be honest I don't have a lot of experience with Grunt or other task runners. The main reason is that when this automation fever started more than a year ago in the front end community, Gulp was my first attempt at it and it was so simple that I've never needed or wanted to try anything else.

In a couple of minutes I was creating tasks, automating processes and making my code better.

# How to install it

If you want to use Gulp the first thing you need to do is to install it globally. Your OS might require super user permission for this, in that case just add sudo at the beginning of it.

npm install -g gulp

Then do it locally in your project's folder.

npm install --save-dev gulp

For every package you want to use, run this command or just add the name of the module with its version to your package.json file and run npm install or do it on your terminal using the --save-dev flag.

npm install --save-dev gulp-uglify

Finally, create a file called gulpfile.js, require all your modules you'll use and you can start automating tasks for your projects.

var gulp = require('gulp');
var rename = require('gulp-rename');
var jshint = require('gulp-jshint');
var uglify = require('gulp-uglify');

# How it works

One of the things you're going to listen or read a lot about Gulp is that it's fast. The reason is that it uses streams, a great feature of NodeJS. Streams are basically chunks of data with an upstream, a start, then piped actions that make modifications on that stream until you get to the end of it, the downstream, where you can report or export the results.

There is a great article about streams in Node written by Sandeep Panda if you find this topic interesting or need a more extensive and probably better explanation about it.

When you declare a task in Gulp, you first choose a source directory.

gulp.task('minify', function () {
  return gulp
    .src('src/**/*.js')
    .pipe(uglify())
    .pipe(
      rename({
        suffix: '.min'
      })
    )
    .pipe(gulp.dest('dist/'));
});

What I've noticed when seeing a code similar to this for the first time was that, while I still had a lot to understand about Gulp and streams, I could totally tell somebody else what was happening. All files inside the folder src with a .js extension are getting uglified, renamed and put inside the dist folder.

Because we are working with streams you always need to return something that can be a file, a file system or another stream, if you don't do it Gulp won't work.

# Conditional tasks

If you want to check your scripts' syntax before minifying them (which you should) then you can create another task for it and tell minify to make sure hint task is finished before starting to minify the files.

gulp.task('hint', function() {
  return gulp.src('src/**/*.js')
	.pipe(jshint());
	.pipe(jshint.reporter('fail'));
});

gulp.task('minify', [ 'hint' ], function() {
  return gulp.src('src/**/*.js')
	.pipe(uglify())
	.pipe(rename({
    	suffix: '.min'
	}))
	.pipe(gulp.dest('dist/'));
});

You can put both tasks into one but I would rather keep them doing just one thing, because you might need to check the style of your code without overriding files in the production folder for example. More and shorter tasks adds more versatility to your workflow.

# Running tasks

Once you've finished writing your tasks, you write the command gulp followed by the name of the task, like minify and you're going to see something like this in your console.

your-pc: to/path/project/ jeremenichelli$ gulp minify
[gulp] Using gulpfile /to/path/project/gulpfile.js
[gulp] Starting 'hint'...
[gulp] Finished 'hint' after 13 μs
[gulp] Starting 'minify'...
[gulp] Finished 'minify' after 42 ms

You can also declare a default task and run it just writing gulp.

gulp.task('default', ['minify']);

# Wrap-up

Gulp is simple and powerful, you can do great things with a short amount of time spent learning. Maybe one of its drawbacks is that it doesn't have a big community as Grunt has. That means less packages, less maintenance and more bugs probably. It's all about choices.

I've created a repository with an initial JavaScript project with a Gulp workflow ready to use so you can take it as a start point or just take a look at it to investigate and learn more about this tool.