Allow auto-expand of accordions based on URL

Author: h-m-m

_layouts/base.html

@@ -153,6 +153,7 @@ <h1 class="usa-display">{{ page.title }}</h1>
     <script src="{{ site.baseurl }}/assets/js/toggle_view.js"></script>
     <script src="{{ site.baseurl }}/assets/js/main.js"></script>
     <script src="{{ site.baseurl }}/assets/js/anchor.js"></script>
+    <script src="{{ site.baseurl }}/assets/js/anchor_accordion.js"></script>
 
     <script>
       anchors.add([

assets/js/anchor_accordion.js

@@ -0,0 +1,16 @@
+(() => {
+  const onChange = (_event) => {
+    const urlHash = new URL(document.URL).hash;
+    const idFromHash = urlHash.match(/^(#[A-Za-z0-9_-]+)$/);
+    if (idFromHash) {
+      const accordionHeading = document.querySelector(
+        `${idFromHash[1]}.usa-accordion__heading > button`,
+      );
+      if (accordionHeading) {
+        accordionHeading.click();
+      }
+    }
+  };
+  document.addEventListener('DOMContentLoaded', onChange);
+  window.addEventListener('hashchange', onChange);
+})();

spec/integration/accordion_js_spec.rb

@@ -2,9 +2,25 @@
 require 'pry-byebug'
 
 RSpec.describe 'accordions on /oidc/authorization/', :js, type: :feature do
-  it 'loads the page' do
-    visit '/oidc/authorization/'
-    first_summary = find_all('summary').first
-    expect(first_summary.text).to eq 'Type of Service Level'
+  it 'is not expanded by default' do
+    visit '/oidc/authorization'
+    expect(page).to have_element('dt')
+    expect(page).to have_no_element('dd')
+    accordion_button = find('#service_level button')
+    expect(accordion_button.native.attribute('aria-expanded')).to eq('false')
   end
-end
+
+  it 'is expanded with an anchor in the URL' do
+    visit '/oidc/authorization#service_level'
+    expect(page).to have_element('dt')
+    expect(page).to have_element('dd')
+    definition = find('#service_level ~ dd').text
+    expect(definition).to include('acr.login.gov:verified')
+    accordion_button = find('#service_level > button')
+    expect(accordion_button.native.attribute('aria-expanded')).to eq('true')
+
+    visit '/oidc/authorization#aal_values'
+    next_definition = find('#aal_values ~ dd').text
+    expect(next_definition).to include('http://idmanagement.gov/ns/assurance/aal/2')
+  end
+end