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Mojolicious::Plugin::Webpack - Mojolicious ♥ Webpack


Define entrypoint

Create a file "./assets/index.js" relative to you application directory with the following content:

  console.log('Cool beans!');


Your Mojolicious application need to load the Mojolicious::Plugin::Webpack plugin and tell it what kind of assets it should be able to process:

  $app->plugin(Webpack => {process => [qw(js css)]});

See "register" for more configuration options.


To include the generated assets in your template, you can use the "asset" helper:

  %= asset "cool_beans.css"
  %= asset "cool_beans.js"

Run the application

You can start the application using daemon, hypnotoad or any Mojolicious server you want, but if you want rapid development you should use mojo webpack, which is an alternative to morbo:

  $ mojo webpack -h
  $ mojo webpack ./script/

However if you want to use another daemon and force webpack to run, you need to set the MOJO_WEBPACK_BUILD environment variable to "1". Example:

  MOJO_WEBPACK_BUILD=1 ./script/ daemon


If you want to make sure you have built all the assets, you can make a test file like "build-assets.t":

  use Test::More;
  use Test::Mojo;

  # Run with TEST_BUILD_ASSETS=1 prove -vl t/build-assets.t
  plan skip_all => "TEST_BUILD_ASSETS=1" unless $ENV{TEST_BUILD_ASSETS};

  # Load the app and make a test object
  $ENV{MOJO_MODE}          = 'production';
  use FindBin;
  require "$FindBin::Bin/../script/";
  my $t = Test::Mojo->new;

  # Find all the tags and make sure they can be loaded
  $t->element_count_is('script[src], link[href][rel=stylesheet]', 2);
  $t->tx->res->dom->find("script[src], link[href][rel=stylesheet]")->each(sub {
    $t->get_ok($_->{href} || $_->{src})->status_is(200);



Mojolicious::Plugin::Webpack is a Mojolicious plugin to make it easier to work with or This plugin will...

  1. Generate a minimal package.json and a Webpack or Rollup config file. Doing this manually is possible, but it can be quite time consuming to figure out all the bits and pieces if you are not already familiar with Webpack.

  2. Load the entrypoint "./assets/index.js", which is the starting point of your client side application. The entry file can load JavaScript, CSS, SASS, ... as long as the appropriate processing plugin is loaded.

  3. It can be difficult to know exactly which plugins to use with Webpack. Because of this Mojolicious::Plugin::Webpack has some predefined rules for which Nodejs dependencies to fetch and install. None of the nodejs modules are required in production though, so it will only be installed while developing.

  4. While developing, the webpack executable will be started automatically next to Mojo::Server::Morbo. Webpack will be started with the appropriate switches to watch your source files and re-compile on change.


rollup.js is an alternative to Webpack. Both accomplish more or less the same thing, but in different ways.

To be able to use rollup, you have to load this plugin with a different engine:

  $app->plugin(Webpack => {engine => 'Mojo::Alien::rollup', process => [qw(js css)]});


Mojolicious::Plugin::Webpack is currently EXPERIMENTAL.



  # Call a method or access an attribute in this class
  my $path = $app->asset->engine->out_dir;

  # Call a method, but from inside a mojo template
  %= asset->url_for($c, "cool_beans.css")

  # Generate a HTML tag
  my $bytestream = $c->asset("cool_beans.js", @args);

  # Generate a HTML tag, but from inside a mojo template
  %= asset "cool_beans.css", media => "print"
  %= asset(url_for => "cool_beans.css")

The most basic usage of this helper is to create a HTML tag using "javascript" in Mojolicious::Plugin::TagHelpers or "stylesheet" in Mojolicious::Plugin::TagHelpers if a valid asset name is passed in.

On the other hand, the helper will return the plugin instance if no arguments are passed in, allowing you to call any of the "METHODS" or access the "ATTRIBUTES".



  $app->before_webpack_start(sub { my $webpack = shift; ... });

Emitted right before the plugin starts building or loading in the generated assets. Useful if you want to change any of the "engine" attributes from the defaults.



  $engine = $webpack->engine;

Returns a Mojo::Alien::webpack or Mojo::Alien::rollup object.



  $hash_ref = $webpack->asset_map;

Reads all the generated files in "asset_path" and returns a hash-ref like this:

    "relative/output.js" => {               # Key is a friendly name, withouc checksum
      ext      => 'css',                    # File extension
      helper   => 'javascript',             # Mojolicious helper used to render the asset
      rel_name => "relative/", # Relative filename with checksum

Note that changing this hash might change how "asset" and "url_for" behaves!


  $webpack->register($app, \%config);
  $app->plugin("Webpack", \%config);

Used to register this plugin into your Mojolicious app.

The %config passed when loading this plugin can have any of these attributes:

  • asset_path

    Can be used to specify an alternative static directory to output the built assets to.

    Default: "/asset".

  • cache_control

    Used to set the response "Cache-Control" header for built assets.

    Default: "no-cache" while developing and "max-age=86400" in production.

  • engine

    Must be a valid engine class name. Examples:

      $app->plugin("Webpack", {engine => 'Mojo::Alien::rollup'});
      $app->plugin("Webpack", {engine => 'Mojo::Alien::webpack'});

    Default: Mojo::Alien::webpack.

  • helper

    Name of the helper that will be added to your application.

    Default: "asset".

  • process

    Used to specify "include" in Mojo::Alien::webpack or "include" in Mojo::Alien::rollup.

    Default: ['js'].


  $url = $webpack->url_for($c, $asset_name);

Returns a Mojo::URL for a given asset.


Jan Henning Thorsen


Copyright (C) Jan Henning Thorsen

This program is free software, you can redistribute it and/or modify it under the terms of the Artistic License version 2.0.


Mojo::Alien::rollup, Mojo::Alien::webpack.