Add service navigation component

packages/govuk-frontend/src/govuk-prototype-kit/govuk-prototype-kit.config.unit.test.mjs

@@ -152,6 +152,10 @@ describe('GOV.UK Prototype Kit config', () => {
           importFrom: 'govuk/components/select/macro.njk',
           macroName: 'govukSelect'
         },
+        {
+          importFrom: 'govuk/components/service-navigation/macro.njk',
+          macroName: 'govukServiceNavigation'
+        },
         {
           importFrom: 'govuk/components/skip-link/macro.njk',
           macroName: 'govukSkipLink'

packages/govuk-frontend/src/govuk/all.mjs

@@ -9,6 +9,7 @@ export { Header } from './components/header/header.mjs'
 export { NotificationBanner } from './components/notification-banner/notification-banner.mjs'
 export { PasswordInput } from './components/password-input/password-input.mjs'
 export { Radios } from './components/radios/radios.mjs'
+export { ServiceNavigation } from './components/service-navigation/service-navigation.mjs'
 export { SkipLink } from './components/skip-link/skip-link.mjs'
 export { Tabs } from './components/tabs/tabs.mjs'
 export { initAll, createAll } from './init.mjs'

packages/govuk-frontend/src/govuk/all.puppeteer.test.js

@@ -60,6 +60,7 @@ describe('GOV.UK Frontend', () => {
         'NotificationBanner',
         'PasswordInput',
         'Radios',
+        'ServiceNavigation',
         'SkipLink',
         'Tabs'
       ])

packages/govuk-frontend/src/govuk/components/_index.scss

@@ -27,6 +27,7 @@
 @import "phase-banner/index";
 @import "radios/index";
 @import "select/index";
+@import "service-navigation/index";
 @import "skip-link/index";
 @import "summary-list/index";
 @import "table/index";

packages/govuk-frontend/src/govuk/components/header/_index.scss

@@ -38,6 +38,14 @@
     border-bottom: $govuk-header-border-width solid $govuk-header-border-color;
   }
 
+  .govuk-header--full-width-border {
+    border-bottom-color: $govuk-header-border-color;
+
+    .govuk-header__container {
+      border-bottom-color: transparent;
+    }
+  }
+
   .govuk-header__logotype {
     display: inline-block;
     position: relative;

packages/govuk-frontend/src/govuk/components/header/header.yaml

@@ -247,6 +247,12 @@ examples:
         - href: '#3'
           text: Navigation item 3
 
+  - name: with full width border
+    description: Makes the header's bottom border full width without affecting the header's content.
+    options:
+      classes: govuk-header--full-width-border
+      productName: Product Name
+
   - name: navigation item with html
     options:
       serviceName: Service Name

packages/govuk-frontend/src/govuk/components/service-navigation/README.md

@@ -0,0 +1,15 @@
+# Service Navigation
+
+## Installation
+
+See the [main README quick start guide](https://github.com/alphagov/govuk-frontend#quick-start) for how to install this component.
+
+## Guidance and Examples
+
+Find out when to use the service header component in your service in the [GOV.UK Design System](https://design-system.service.gov.uk/components/service-navigation).
+
+## Component options
+
+Use options to customise the appearance, content and behaviour of a component when using a macro, for example, changing the text.
+
+See [options table](https://design-system.service.gov.uk/components/service-navigation/#options-service-navigation-example) for details.

packages/govuk-frontend/src/govuk/components/service-navigation/_index.scss

@@ -0,0 +1,160 @@
+@include govuk-exports("govuk/component/service-navigation") {
+  $govuk-service-navigation-active-link-border-width: govuk-spacing(1);
+  $govuk-service-navigation-background: $govuk-canvas-background-colour;
+  $govuk-service-navigation-border-colour: $govuk-border-colour;
+
+  // We make the link colour a little darker than normal here so that it has
+  // better perceptual contrast with the navigation background.
+  $govuk-service-navigation-link-colour: govuk-shade($govuk-link-colour, 10%);
+
+  .govuk-service-navigation {
+    border-bottom: 1px solid $govuk-service-navigation-border-colour;
+    background-color: $govuk-service-navigation-background;
+  }
+
+  .govuk-service-navigation__container {
+    display: flex;
+    flex-direction: column;
+    align-items: start;
+
+    @include govuk-media-query($from: tablet) {
+      flex-direction: row;
+      flex-wrap: wrap;
+    }
+  }
+
+  // These styles are shared between nav items and the service name, they
+  // ensure that both of them remain vertically aligned with one another
+  .govuk-service-navigation__item,
+  .govuk-service-navigation__service-name {
+    position: relative;
+    margin: govuk-spacing(2) 0;
+    border: 0 solid $govuk-service-navigation-link-colour;
+
+    @include govuk-media-query($from: tablet) {
+      margin-top: 0;
+      margin-bottom: 0;
+      padding: govuk-spacing(4) 0;
+
+      &:not(:last-child) {
+        @include govuk-responsive-margin(6, $direction: right);
+      }
+    }
+  }
+
+  .govuk-service-navigation__item--active {
+    @include govuk-media-query($until: tablet) {
+      // Negative offset the left margin so we can place a current page indicator
+      // to the left without misaligning the list item text.
+      margin-left: ((govuk-spacing(2) + $govuk-service-navigation-active-link-border-width) * -1);
+      padding-left: govuk-spacing(2);
+      border-left-width: $govuk-service-navigation-active-link-border-width;
+    }
+
+    @include govuk-media-query($from: tablet) {
+      padding-bottom: govuk-spacing(4) - $govuk-service-navigation-active-link-border-width;
+      border-bottom-width: $govuk-service-navigation-active-link-border-width;
+    }
+  }
+
+  .govuk-service-navigation__link {
+    @include govuk-link-common;
+    @include govuk-link-style-no-underline;
+    @include govuk-link-style-no-visited-state;
+
+    &:not(:hover):not(:focus) {
+      // We set the colour here as we don't want to override the hover or
+      // focus colours
+      color: $govuk-service-navigation-link-colour;
+    }
+  }
+
+  //
+  // Service name specific code
+  //
+
+  .govuk-service-navigation__service-name {
+    @include govuk-font($size: 19, $weight: bold);
+  }
+
+  // Annoyingly this requires a compound selector in order to overcome the
+  // specificity of the other link colour override we're doing
+  .govuk-service-navigation__service-name .govuk-service-navigation__link {
+    @include govuk-link-style-text;
+  }
+
+  //
+  // Navigation list specific code
+  //
+
+  .govuk-service-navigation__toggle {
+    @include govuk-font($size: 19, $weight: bold);
+    display: inline-flex;
+    margin: 0 0 govuk-spacing(2);
+    padding: 0;
+    border: 0;
+    color: $govuk-service-navigation-link-colour;
+    background: none;
+    word-break: break-all;
+    cursor: pointer;
+    align-items: center;
+
+    &:focus {
+      @include govuk-focused-text;
+    }
+
+    &::after {
+      @include govuk-shape-arrow($direction: down, $base: 10px, $display: inline-block);
+      content: "";
+      margin-left: govuk-spacing(1);
+    }
+
+    &[aria-expanded="true"]::after {
+      @include govuk-shape-arrow($direction: up, $base: 10px, $display: inline-block);
+    }
+
+    // Ensure the button stays hidden if the hidden attribute is present
+    &[hidden] {
+      display: none;
+    }
+  }
+
+  .govuk-service-navigation__list {
+    @include govuk-font($size: 19);
+    margin: 0;
+    margin-bottom: govuk-spacing(3);
+    padding: 0;
+    list-style: none;
+
+    // Make the navigation list a flexbox. Doing so resolves a couple of
+    // accessibility problems caused by the list items being inline-blocks:
+    // - Removes the extra whitespace from between each list item that screen
+    //   readers would pointlessly announce.
+    // - Fixes an NVDA issue in Firefox and Chrome <= 124 where it would read
+    //   all of the links as a run-on sentence.
+    @include govuk-media-query($from: tablet) {
+      display: flex;
+      flex-wrap: wrap;
+      margin-bottom: 0;
+
+      // However... IE11 totally trips over flexbox and doesn't wrap anything,
+      // making all of the items into a single, horizontally scrolling row,
+      // which is no good. This CSS hack removes the flexbox definition for
+      // IE 10 & 11, reverting it to the flawed, but OK, non-flexbox version.
+      //
+      // CSS hack taken from https://stackoverflow.com/questions/11173106/apply-style-only-on-ie#answer-36448860
+      // which also includes an explanation of why this works
+      @media screen and (-ms-high-contrast: active), (-ms-high-contrast: none) {
+        display: block;
+      }
+    }
+  }
+
+  // This is a <strong> element that is used as a fallback mechanism for
+  // visually indicating the current page in scenarios where CSS isn't
+  // available. We don't actually want it to be bold normally, so set it to
+  // inherit the parent font-weight.
+  .govuk-service-navigation__active-fallback {
+    font-weight: inherit;
+  }
+}

packages/govuk-frontend/src/govuk/components/service-navigation/_service-navigation.scss

@@ -0,0 +1,2 @@
+@import "../../base";
+@import "./index";

packages/govuk-frontend/src/govuk/components/service-navigation/accessibility.puppeteer.test.mjs

@@ -0,0 +1,30 @@
+import { axe, render } from '@govuk-frontend/helpers/puppeteer'
+import { getExamples } from '@govuk-frontend/lib/components'
+
+describe('/components/service-navigation', () => {
+  let axeRules
+
+  beforeAll(() => {
+    axeRules = {
+      /**
+       * Ignore 'Element has insufficient color contrast' for WCAG Level AAA
+       */
+      'color-contrast-enhanced': { enabled: false }
+    }
+  })
+
+  describe('component examples', () => {
+    it('passes accessibility tests', async () => {
+      const examples = await getExamples('service-navigation')
+
+      // Remove the 'with no options set' example from being tested, as the
+      // component doesn't output anything in that scenario.
+      delete examples['with no options set']
+
+      for (const exampleName in examples) {
+        await render(page, 'service-navigation', examples[exampleName])
+        await expect(axe(page, axeRules)).resolves.toHaveNoViolations()
+      }
+    }, 120000)
+  })
+})

packages/govuk-frontend/src/govuk/components/service-navigation/macro.njk

@@ -0,0 +1,3 @@
+{% macro govukServiceNavigation(params) %}
+  {%- include "./template.njk" -%}
+{% endmacro %}