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Installing GOV.UK Frontend with node package manager (NPM)

Requirements

To use GOV.UK Frontend with NPM you must:

  1. Install the long-term support (LTS) version of Node.js, which includes NPM. The minimum version of Node required is 4.2.0.

    (We recommend using nvm for managing versions of Node.)

  2. Create a package.json file if you don’t already have one. You can create a default package.json file by running npm init from the root of your application.

  3. If you want to use the GOV.UK Frontend Nunjucks macros, install Nunjucks - the minimum version required is 3.0.0.

npm install nunjucks --save

Installation

To install, run:

npm install --save govuk-frontend

After you have installed GOV.UK Frontend the govuk-frontend package will appear in your node_modules folder.

Importing styles

You need to import the GOV.UK Frontend styles into the main Sass file in your project. You should place the below code before your own Sass rules (or Sass imports) if you want to override GOV.UK Frontend with your own styles.

  1. To import all components, add the below to your Sass file:
@import "node_modules/govuk-frontend/all";
  1. To import an individual component (for example a button), add the below to your Sass file:
@import "node_modules/govuk-frontend/components/button/button";

Optional: Resolving SCSS import paths

If you wish to resolve the above @import paths in your build (in order to avoid prefixing paths with node_modules), you should add node_modules to your Sass include paths (in Ruby, they should be added to assets paths).

For example, if your project uses Gulp, you would add the Sass include paths to your Gulp configuration file (for example gulpfile.js) with gulp-sass. Below is an example:

gulp.task('sass', function () {
  return gulp.src('./sass/**/*.scss')
    .pipe(sass({
      includePaths: 'node_modules'
     }))
    .pipe(gulp.dest('./css'));
});

If you compile Sass to CSS in your project, your build tasks will already include something similar to the above task - in that case, you will just need to include add includePaths to it.

After resolving the import paths you can import GOV.UK Frontend by using:

@import "govuk-frontend/components/button/button";

Global Styles

GOV.UK Frontend avoids applying styles globally on HTML elements such as body; instead, styles are are applied using classes.

This to avoid the risk of global styles conflicting with any pre-existing globals, for example in GOV.UK Elements or GOV.UK Template, or with any app specific CSS.

Hovever, we do include some global styles in the GOV.UK Prototype Kit to speed up prototyping.

These global styles are are not included by default in GOV.UK Frontend. To include these global styles in your app, you can set $govuk-global-styles variable to true before importing GOV.UK Frontend styles into your app:

// application.scss

$govuk-global-styles: true;

@import "govuk-frontend/all";

Compatibility mode

GOV.UK Frontend includes additional styles that can be enabled to allow support for deprecated projects such as GOV.UK Elements, GOV.UK Template, GOV.UK Frontend Toolkit.

Setting compatibility SCSS variables will change how GOV.UK Frontend's CSS renders to work around global styles that conflict with GOV.UK Frontend.

To enable this feature include the SCSS variables that correspond with the projects you depend on before importing GOV.UK Frontend styles into your app:

// application.scss

$govuk-compatibility-govukfrontendtoolkit: true;
$govuk-compatibility-govuktemplate: true;
$govuk-compatibility-govukelements: true;

@import "govuk-frontend/all";

Using JavaScript

Some of the JavaScript included in GOV.UK Frontend improves the usability and accessibility of the components.

For example, the JavaScript will:

  • allow links styled as buttons to be triggered with the space bar when focused, which matches the behaviour of native buttons and the way the button is described when using assistive technologies.
  • enhance the details component to help users of assistive technologies understand whether it is expanded or collapsed, and to make the component behave correctly for users of Internet Explorer 8.

You should include or import GOV.UK Frontend JavaScript, and then initialise the script in your application to ensure that all users can use it successfully.

Note that GOV.UK Frontend does not initialise any scripts by default; all scripts must be initialised in order for them to work.

Option 1: Include JavaScript

Include the node_modules/govuk-frontend/all.js script on your page. You might wish to copy the file into your project or reference it from node_modules.

To initialise all components, use the initAll function.

JavaScript in GOV.UK Frontend requires HTML to be parsed first by the browser before it is initialised. Because of this, make sure you include the script before the closing </body> tag. Including the script elsewhere will stop components from functioning or displaying correctly.

    <script src="path-to-assets/govuk-frontend/all.js"></script>
    <script>window.GOVUKFrontend.initAll()</script>
  </body>
</html>

Initialise GOV.UK Frontend in only certain sections of a page

By default, the initAll function from GOV.UK Frontend initialises all components scoped to an entire page with the document object.

You can change this by passing the scope parameter to the initAll function.

For example, if you have a modal dialog box that opens with new markup you could do the following:

var $modal = document.querySelector('.modal')
window.GOVUKFrontend.initAll({
  scope: $modal
})

Initialise individual included components

GOV.UK Frontend components with JavaScript behaviour have the data-module attribute set in their markup.

You can use this attribute to initialise the component manually. This may be useful if you are adding markup to a page after it has loaded.

To initialise the first radio component on a page, use:

var Radios = window.GOVUKFrontend.Radios
var $radio = document.querySelector('[data-module="radios"]')
if ($radio) {
  new Radios($radio).init()
}

Some components such as the details or button components are initialised globally. If you want to see how these are initialised by default, see the all.js file.

Option 2: Import JavaScript

If you're using a bundler such as Webpack, use the import syntax to import all components. To initialise them, use the initAll function:

import { initAll } from 'govuk-frontend'

initAll()

If you're using a bundler such as Browserify, you may need to use the CommonJS require:

const GOVUKFrontend = require('govuk-frontend')

GOVUKFrontend.initAll()

Import individual components

If you're using a bundler such as Webpack, use the import syntax to import a component:

import { Radios } from 'govuk-frontend'

If you're using a bundler such as Browserify, you may need to use the CommonJS require:

const GOVUKFrontend = require('govuk-frontend')

const Radios = GOVUKFrontend.Radios

GOV.UK Frontend components with JavaScript behaviour have the data-module attribute set in their markup.

You can use this attribute to initialise the component manually, this may be useful if you are adding markup to a page after it has loaded.

To initialise the first radio component on a page, use:

var $radio = document.querySelector('[data-module="radios"]')
if ($radio) {
  new Radios($radio).init()
}

Some components such as the details or button components are initialised globally. If you want to see how these are initialised by default, see the all.js file.

Polyfills

A JavaScript polyfill provides functionality on older browsers or assistive technology that do not natively support it.

The polyfills provided with GOV.UK Frontend aim to fix usability and accessibility issues. If there is a JavaScript included in the component directory, it is important to import and initialise it in your project to ensure that all users can properly use the component (see Polyfilling).

How GOV.UK Frontend is bundled

The JavaScript included in GOV.UK Frontend components are in UMD (Universal Module Definition) format which makes it compatible with AMD (Asynchronous module definition) and CommonJS.

See JavaScript Coding Standards for more details of how JavaScript is used in the project.

Using GOV.UK Frontend with Webpack 4

Here's an example of setting up webpack.config.js in your project

Importing assets

In order to import GOV.UK Frontend images and fonts to your project, you should configure your application to reference or copy the relevant GOV.UK Frontend assets.

Follow either Recommended solution or Alternative solution.

Recommended solution

Make /node_modules/govuk-frontend/assets available to your project by routing requests for your assets folder there.

For example, if your project uses express.js, below is a code sample you could add to your configuration:

app.use('/assets', express.static(path.join(__dirname, '/node_modules/govuk-frontend/assets')))

Alternative solution

Manually copy the images and fonts from /node_modules/govuk-frontend/assets into a public facing directory in your project. Ideally copying the files to your project should be an automated task or part of your build pipeline to ensure that the GOV.UK Frontend assets stay up-to-date.

The default paths used for assets are assets/images and assets/fonts. If your asset folders follow this structure, you will not need to complete the following steps.

To use different asset paths, also complete the below step(s).

  1. Set $govuk-assets-path, $govuk-images-path and $govuk-fonts-path in your project Sass file to point to the relevant directories in your project (this will override the defaults set in /node_modules/govuk-frontend/settings/_assets.scss). Make sure you do this in Sass before importing govuk-frontend into your project - see Importing styles.

Example 1:

// Include images from /application/assets/images and fonts from /application/assets/fonts
$govuk-assets-path: '/application/assets';

@import "govuk-frontend/all";

Example 2:

// Include images from /images/govuk-frontend and fonts from /fonts
$govuk-images-path: "/images/govuk-frontend/";
$govuk-fonts-path: "/fonts/";

@import "govuk-frontend/all";
  1. Optional: You can also override the helpers used to generate the asset urls, for example if you are using sass-rails' asset-pipeline functionality. You can do this by setting $govuk-image-url-function to the name of the function(s) you wish to use. See src/settings/_assets.scss for more information and examples.

Include CSS and JavaScript

Add the CSS and JavaScript code to your HTML template:

<!DOCTYPE html>
  <head>
    <title>Example</title>
    <link rel="stylesheet" href="assets/application.css">
  </head>
  <body>
    <!-- Copy and paste component HTML-->
    <button class="govuk-button">This is a button component</button>
    <script src="assets/application.js"></script>
  </body>
</html>

If your service supports Internet Explorer 8, you will need to generate and include a separate stylesheet as well.