[5.8] Allow configuring a default manifest directory

[CupOfTea696]

This PR depends on laravel/laravel#4957.

This PR enables users to set a default manifest directory for all calls to the mix helper, so that they don't have to pass a second parameter to it every time. It also makes it less likely that a user will forget to pass the manifest directory to the mix helper. An additional benefit is that, if they would ever change this path, they can now change it in a single location, rather than having to go through all their views. It is also makes it easy to change this path in different environments.

This PR doesn't break any existing features. It only adds one additional line to the Mix class and doesn't change its signature. The behaviour of the helper function stays the same if the configuration value isn't set.

Example usage:

In webpack.mix.js

mix.setPublicPath('public/assets');
mix.sass('resources/assets/scss/app.scss', 'public/assets/css')
    .version();

In config/app.php

<?php

return [
    ...

    'manifest_directory' => env('MANIFEST_DIRECTORY', ''),

    ...
];

And then finally, in any view file:

<link rel="stylesheet" href="{{ mix('css/app.css') }}">
<!-- renders to <link rel="stylesheet" href="/assets/css/app.css?id=123"> -->

Previously, you'd have to use the following every time you used a mix asset:

<link rel="stylesheet" href="{{ mix('css/app.css', 'assets') }}">

[ludo237]

Wait... I never had to pass the manifest directory inside mix function 😕

[CupOfTea696]

@ludo237 You don't have to if you let it compile to the default directory.

I personally always compile my assets to public/assets as to not clutter my public directory too much.

[ludo237]

Thanks for the explanation, now it makes sense

[timacdonald]

Because mix is now bound to the container, you should be able to do this without any config. Lemme see if I can put together an example.

[timacdonald]

Yea, you could just do this in your app by swapping out the mix implementation with an extended class that has the default value, instead of introducing a framework wide config variable.

Take a look at this slightly adjusted, and passing, version of your test.

public function testMixWithConfiguredManifestDirectory()
{
-    app('config')->set(['app.manifest_directory' => 'mix']);
+    $this->swap(Mix::class, new class extends Mix {
+        public function __invoke($path, $manifestDirectory = 'mix') {
+           return parent::__invoke($path, $manifestDirectory);
+        }
+    });

    mkdir($directory = __DIR__.'/mix');
    $manifest = $this->makeManifest('mix');

    $result = mix('unversioned.css');

    $this->assertSame('/mix/versioned.css', $result->toHtml());

    unlink($manifest);
    rmdir($directory);

-    app('config')->set(['app.manifest_directory' => '']);
}

That allows you to set a default value for the mix directory. You could just swap the mix singleton in you app service provider and this should work perfect.

[taylorotwell]

Thanks for your pull request to Laravel!

Unfortunately, I'm going to delay merging this code for now. To preserve our ability to adequately maintain the framework, we need to be very careful regarding the amount of code we include.

If possible, please consider releasing your code as a package so that the community can still take advantage of your contributions!

If you feel absolutely certain that this code corrects a bug in the framework, please "@" mention me in a follow-up comment with further explanation so that GitHub will send me a notification of your response.