Browser compilation library – an asset pipeline for applications that run in the browser
Latest commit 9f6ee48 Oct 26, 2018

README.md

Broccoli

Build Status Build status

A fast, reliable asset pipeline, supporting constant-time rebuilds and compact build definitions. Comparable to the Rails asset pipeline in scope, though it runs on Node and is backend-agnostic. For background and architecture, see the introductory blog post.

For the command line interface, see broccoli-cli.

Installation

npm install --save-dev broccoli
npm install --global broccoli-cli

Brocfile.js

A Brocfile.js file in the project root contains the build specification. It should export a tree.

A tree can be any string representing a directory path, like 'app' or 'src'. Or a tree can be an object conforming to the Plugin API Specification. A Brocfile.js will usually directly work with only directory paths, and then use the plugins in the Plugins section to generate transformed trees.

The following simple Brocfile.js would export the app/ subdirectory as a tree:

module.exports = 'app'

With that Brocfile, the build result would equal the contents of the app tree in your project folder. For example, say your project contains these files:

app
├─ main.js
└─ helper.js
Brocfile.js
package.json
…

Running broccoli build the-output (a command provided by broccoli-cli) would generate the following folder within your project folder:

the-output
├─ main.js
└─ helper.js

Using plugins in a Brocfile.js

The following Brocfile.js exports the app/ subdirectory as appkit/:

var Funnel = require('broccoli-funnel')

module.exports = new Funnel('app', {
  destDir: 'appkit'
})

That example uses the plugin broccoli-funnel. In order for the require call to work, you must first put the plugin in your devDependencies and install it, with

npm install --save-dev broccoli-funnel

With the above Brocfile.js and the file tree from the previous example, running broccoli build the-output would generate the following folder:

the-output
└─ appkit
   ├─ main.js
   └─ helper.js

Plugins

You can find plugins under the broccoli-plugin keyword on npm.

Using Broccoli Programmatically

In addition to using Broccoli via the combination of broccoli-cli and a Brocfile.js, you can also use Broccoli programmatically to construct your own build output via the Builder class. The Builder is one of the core APIs in Broccoli, and is responsible for taking a graph of Broccoli nodes and producing an actual build artifact (i.e. the output usually found in your dist directory after you run broccoli build). The output of a Builder's build method is a Promise that resolves when all the operations in the graph are complete. You can use this promise to chain together additional operations (such as error handling or cleanup) that will execute once the build step is complete.

By way of example, let's assume we have a graph of Broccoli nodes constructed via a combination of Funnel and MergeTrees:

const html = new Funnel(appRoot, {
  files: ['index.html'],
  annotation: 'Index file'
})

const js = new Funnel(appRoot, {
  files: ['app.js'],
  destDir: '/assets',
  annotation: 'JS Files'
});

const css = new Funnel(appRoot, {
  srcDir: 'styles',
  files: ['app.css'],
  destDir: '/assets',
  annotation: 'CSS Files'
});

const public = new Funnel(appRoot, {
  annotation: 'Public Files'
});

const tree = new Merge([html, js, css, public]);

At this point, tree is a graph of nodes, each of which can represent either an input or a transformation that we want to perform. In other words, tree is an abstract set of operations, not a concrete set of output files.

In order to perform all the operations described in tree, we need to do the following:

  • construct a Builder instance, passing in the graph we constructed before
  • call the build method, which will traverse the graph, performing each operation and eventually writing the output to a temporary folder indicated by builder.outputPath

Since we typically want do more than write to a temporary folder, we'll also use a library called TreeSync to sync the contents of the temp file with our desired output directory. Finally, we'll clean up the temporary folder once all our operations are complete:

const { Builder } = require('broccoli');
const TreeSync = require('tree-sync');
// ...snip...
const tree = new Merge([html, js, css, public]);

const builder = new Builder(tree);

const outputDir = 'dist';
const outputTree = new TreeSync(builder.outputPath, outputDir);

builder.build()
  .then(() => {
    // Calling `sync` will synchronize the contents of the builder's `outPath` with our output directory.
    return outputTree.sync();
  })
  .then(() => {
    // Now that we're done with the build, clean up any temporary files were created
    return builder.cleanup();
  })
  .catch(err => {
    // In case something in this process fails, we still want to ensure that we clean up the temp files
    console.log(err);
    return builder.cleanup();
  });

Running Broccoli, Directly or Through Other Tools

Helpers

Shared code for writing plugins.

Plugin API Specification

See docs/node-api.md.

Also see docs/broccoli-1-0-plugin-api.md on how to upgrade from Broccoli 0.x to the Broccoli 1.x API.

Security

  • Do not run broccoli serve on a production server. While this is theoretically safe, it exposes a needlessly large amount of attack surface just for serving static assets. Instead, use broccoli build to precompile your assets, and serve the static files from a web server of your choice.

Get Help

  • IRC: #broccolijs on Freenode. Ask your question and stick around for a few hours. Someone will see your message eventually.
  • Twitter: mention @jo_liss with your question
  • GitHub: Open an issue on a specific plugin repository, or on this repository for general questions.

License

Broccoli was originally written by Jo Liss and is licensed under the MIT license.

The Broccoli logo was created by Samantha Penner (Miric) and is licensed under CC0 1.0.