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Minify and Combine JavaScript

Now for the most thrilling part: JavaScript. Create a new js directory inside app/Resources/assets and a new file - let's call that main.js.

Ok, let's start with a jQuery document ready block and then log a movie quote that combines two of my favorite things: UNIX and dinosaurs. Thank you Michael Crichton. Let's add something visual to the bottom navbar too. A subtle warning, if you will.

5 lines app/Resources/assets/js/main.js
$(document).ready(function() {
console.log('It\'s a Unix system, I know this');
$('.navbar-static-bottom').prepend('<span class="navbar-text">Life finds a way</span>');
});

With such a cool JavaScript file, I can't wait to include it on my site. But, I can't just go add a script tag - main.js isn't in a public directory. Gulp, halp!

scripts Task in Gulp

Create a new task called scripts:

60 lines gulpfile.js
... lines 1 - 38
gulp.task('scripts', function() {
... lines 40 - 51
});
... lines 53 - 60

Inside here, we're going to do almost the exact same stuff we do with our CSS. So let's copy the inside of addStyle and paste it in our task. Now we need to make a bunch of small adjustments.

First, get rid of a few things, like the sass filter and minifyCss. We will minify in a second, but we need to use a different tool.

Second, in src(), start with config.assetsDir then /js/main.js. We also need jQuery. That already lives inside the bower_components directory. So above main.js, add config.bowerDir - that new config sure is coming in handy - then /jquery/dist/jquery.js.

And to put the cherry on top, change the dest() to web/js and give concat() a filename - how about site.js.

60 lines gulpfile.js
... lines 1 - 38
gulp.task('scripts', function() {
gulp.src([
config.bowerDir+'/jquery/dist/jquery.js',
config.assetsDir+'/js/main.js'
])
.pipe(plugins.plumber(function(error) {
console.log(error.toString());
this.emit('end');
}))
.pipe(plugins.if(config.sourceMaps, plugins.sourcemaps.init()))
.pipe(plugins.concat('site.js'))
.pipe(plugins.if(config.sourceMaps, plugins.sourcemaps.write('.')))
.pipe(gulp.dest('web/js'));
});
... lines 53 - 60

Perfect. We're reusing all that good stuff we learned earlier!

Exit out of gulp with ctrl+c then just try running gulp scripts:

gulp scripts

Now in web/, we have a new site.js file and its map. So with almost no work, JS processing is alive!

Updating watch and default

Let's update the watch task so that the evil robots also rebuild things whenever we update a JS file. Copy the existing line. For the path, have it look for anything in the js directory recursively - so js/**/*.js. And when that happens, run scripts:

54 lines gulpfile.js
... lines 1 - 47
gulp.task('watch', function() {
gulp.watch(config.assetsDir+'/'+config.sassPattern, ['styles']);
gulp.watch(config.assetsDir+'/js/**/*.js', ['scripts']);
});
... lines 52 - 54

Add this to the default task too:

54 lines gulpfile.js
... lines 1 - 52
gulp.task('default', ['styles', 'scripts', 'watch']);

Let's exercise the whole system. Go back and just run gulp:

gulp

Great, it runs scripts and then the watch waits. To test that, go back and add a period to main.js, save and you can see that scripts ran again automatically.

After all this, we have a real site.js file in a public directory! We can now use that to add a boring script tag to our layout. Near the bottom, add the script tag. For the path, I'm using the asset() function from Symfony, but it doesn't really do anything. Say, js/site.js:

48 lines app/Resources/views/base.html.twig
... lines 1 - 42
{% block javascripts %}
<script src="{{ asset('js/site.js') }}"></script>
{% endblock %}
... lines 46 - 48

Ok, refresh! Go down to the bottom, yes! There's our cryptic "Life finds a way" message. And if I bring up the debugger, I can see the UNIX line in the console. The whole thing works great.

Don't Commit web/js

Now, nobody likes it when you commit generated files. And that's what lives in web/js. So, make sure you add this path to your .gitignore:

17 lines .gitignore
... lines 1 - 14
/web/js
... lines 16 - 17

Minify with gulp-uglify

One last challenge: site.js is not minified yet. Dinosaurs hate whitespace, so let's fix that. For our styles, we used that minifyCss plugin. For JS, we'll use one called gulp-uglify. Grab its perfect install statement, stop gulp, and get that downloading:

npm install --save-dev gulp-uglify

We don't need the require line though, because gulp-plugins-require takes care of that for us. We can go straight to work. Copy the minifyCss line so that we have the cool --production flag behavior. Paste it and change things to say plugins.uglify():

55 lines gulpfile.js
... lines 1 - 35
gulp.task('scripts', function() {
gulp.src([
config.bowerDir+'/jquery/dist/jquery.js',
config.assetsDir+'/js/main.js'
])
... lines 41 - 43
.pipe(config.production ? plugins.uglify() : plugins.util.noop())
.pipe(plugins.if(config.sourceMaps, plugins.sourcemaps.write('.')))
.pipe(gulp.dest('web/js'));
});
... lines 48 - 55

Cool! Try it out first with just gulp:

gulp

This should give us the non-minified version. Excellent! Now ctrl+c that and try again with --production:

gulp --production

That file has been uglified! That kind of sounds like a Harry Potter spell. Uglify!

Multiple JavaScript Files

Oh yea, back to dinosaurs. Eventually, we may want some page-specific JavaScript files.

So, add a new app.addScript function with paths and filename arguments. Copy all of the scripts task, paste it, and update src() with paths and site.js with filename:

65 lines gulpfile.js
... lines 1 - 26
app.addScript = function(paths, outputFilename) {
gulp.src(paths)
.pipe(plugins.plumber(function(error) {
console.log(error.toString());
this.emit('end');
}))
.pipe(plugins.if(config.sourceMaps, plugins.sourcemaps.init()))
.pipe(plugins.concat(outputFilename))
.pipe(config.production ? plugins.uglify() : plugins.util.noop())
.pipe(plugins.if(config.sourceMaps, plugins.sourcemaps.write('.')))
.pipe(gulp.dest('web/js'));
};
... lines 39 - 65

Back in the scripts task, we can just call that function. So, app.addScript, keep those paths, then pass site.js:

59 lines gulpfile.js
... lines 1 - 45
gulp.task('scripts', function() {
app.addScript([
config.bowerDir+'/jquery/dist/jquery.js',
config.assetsDir+'/js/main.js'
], 'site.js');
});
... lines 52 - 59

Delete site.js and try it!

gulp

On hey, welcome back site.js. Now when you need a page-specific JavaScript file, just add another addScript call here. Feeling powerful?

What else can you do? Well, if you're into CoffeeScript, you can grab a plugin for that and mix it right in. Do whatever you want.

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