SVG Core Plugins

The SVG Core library includes a Plugins architecture so you can limit the file size and improve performance with only the features you need.

Before You Get Started

Make sure you already:

Set up access to the Javascript API in your project.

Font Awesome Can Do a Lot

Here are the plugins:

Plugin name	What it does
InjectCSS	Adds CSS to the `<head>` of the page that is needed to display icons
ReplaceElements	Replaces `<i>` elements with `<svg>` icons
Layers	Support for layers
LayersCounter	Support for layer counters
LayersText	Support for layer text
PseudoElements	Support for pseudo-elements
MutationObserver	Watches the page (DOM) for changes and replaces elements (`i` to `svg`)
PowerTransforms	Support for Power Transforms
Masks	Support for masking
MissingIconIndicator	Mark missing icons with an animated indicator
SvgSymbols	Support for SVG symbols

When you import anything from @fortawesome/fontawesome-svg-core it comes with all batteries included.

But with a few small changes you can pick the plugins you wish to use. This saves bytes and can improve performance if you aren't wasting time doing unnecessary things.

An Example

This example is using Rollup.js (opens new window) but the same principles apply to most other projects that use Webpack or even tools like ESBuild.

mkdir fa-lite
cd fa-lite

npm init -y

This will create a package.json file in the fa-lite.

Next up is installing some dependencies for Rollup and Font Awesome. (Don't act surprised, you kinda knew we'd be installing some deps didn't you?)

Pro Plan Required

Installing @fortawesome/pro-solid-svg-icons requires a Pro Plan and a Pro Package Token. Get your package manager set up for Pro

npm install --save-dev rollup @rollup/plugin-node-resolve rollup-plugin-terser
npm i --save-dev @fortawesome/fontawesome-svg-core @fortawesome/pro-solid-svg-icons

Create src/fontawesome.js

import { library, dom } from '@fortawesome/fontawesome-svg-core'
import { faAlicorn, faAlien, faBoombox } from '@fortawesome/pro-solid-svg-icons'

library.add(
  faAlicorn,
  faAlien,
  faBoombox
)

window.addEventListener('DOMContentLoaded', () => {
  dom.i2svg()
  dom.watch()
})

Create rollup.config.js

import resolve from '@rollup/plugin-node-resolve'

const plugins = [
  resolve()
]

export default [
  {
    input: 'src/fontawesome.js',
    output: {
      file: 'dist/fontawesome.js',
      format: 'esm'
    },
    plugins
  }
]

Open a terminal in the current directory and we'll run Rollup with --watch:

npx rollup -c rollup.config.js --watch

rollup v2.56.3
bundles src/fontawesome.js → dist/fontawesome.js...
created dist/fontawesome.js in 536ms

[2021-09-13 15:03:39] waiting for changes...

Create index.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
    <script src="dist/fontawesome.js" type="module"></script>
  </head>
  <body>
    <i class="fas fa-alien"></i>
  </body>
</html>

Open another terminal in the current directory and we'll run a small HTTP server:

npm install --save-dev http-server
npx http-server

Starting up http-server, serving ./

http-server settings:
CORS: disabled
Cache: 3600 seconds
Connection Timeout: 120 seconds
Directory Listings: visible
AutoIndex: visible
Serve GZIP Files: false
Serve Brotli Files: false
Default File Extension: none

Available on:
  http://127.0.0.1:8080
  http://127.51.68.120:8080
  http://192.168.4.22:8080
  http://192.168.4.42:8080
Hit CTRL-C to stop the server

Load this up in the browser to see an alien icon.

Switching to Plugins

While the icons have been subsetted you are still including every single one of the features Font Awesome provides.

Create src/fontawesome-lite.js next:

import {
  register,
  InjectCSS,
  ReplaceElements
} from '@fortawesome/fontawesome-svg-core/plugins'

const api = register([InjectCSS, ReplaceElements])

import { faAlicorn, faAlien, faBoombox } from '@fortawesome/pro-solid-svg-icons'

api.library.add(
  faAlicorn,
  faAlien,
  faBoombox
)

window.addEventListener('DOMContentLoaded', () => {
  api.dom.i2svg()
  api.dom.watch()
})

The `api` object changes subtly

An important point to make here is that the api object is now created by calling register() from the @fortawesome/fontawesome-svg-core/plugins module. Calls to things like library.add() will need to become api.library.add(). If you are importing anything from @fortawesome/fontawesome-svg-core (without plugins) you'll lose the benefits of the plugin system altogether.

Modify rollup.config.js

 
import resolve from '@rollup/plugin-node-resolve'

const plugins = [
  resolve()
]

if (process.env.NODE_ENV === 'production') {
  plugins.push(require('rollup-plugin-terser').terser())
}

export default [
  {
    input: 'src/fontawesome.js',
    output: {
      file: 'dist/fontawesome.js',
      format: 'esm'
    },
    plugins
  },
  {
    input: 'src/fontawesome-lite.js',
    output: {
      file: 'dist/fontawesome-lite.js',
      format: 'esm'
    },
    plugins
  }
]

Since we've changed rollup.config.js we need to stop and re-start. Type CTRL+C and then run Rollup again.

npx rollup -c rollup.config.js --watch

Change dist/fontawesome.js to use our dist/fontawesome-lite.js version

 






<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
    <script src="dist/fontawesome-lite.js" type="module"></script>
  </head>
  <body>
    <i class="fas fa-alien"></i>
  </body>
</html>

What to Expect

Compare the file-sizes before and after using the plugin system.

The following sizes were measured using a code minifier called Terser

Terser is already included in this example because you installed it earlier. Run NODE_ENV=production npx rollup -c rollup.config.js to use it.

Filename	Size
dist/fontawesome.js	61k
dist/fontawesome-lite.js	45k

Well, butter my bread! That's 16k saved. Using "lite" may be a bit generous, but we'll be continuing to improve this API as time goes on. This architecture also promises to open up some new possibilities with Font Awesome in the future.