From cbffa2a3409ddf27f88ef489bb81f5d9b907a201 Mon Sep 17 00:00:00 2001
From: Sarah German <sgerman@gitlab.com>
Date: Mon, 14 Aug 2023 21:38:11 +0000
Subject: Scroll to search query on result pages

---
 content/assets/stylesheets/stylesheet.scss         |  5 ++
 .../frontend/search/components/lunr_results.vue    |  7 ++-
 content/frontend/search/google.js                  |  3 +-
 content/frontend/search/lunrsearch.js              | 42 +++++++++--------
 content/frontend/search/search_helpers.js          | 55 ++++++++++++++++++++++
 content/frontend/services/google_search_api.js     |  7 ++-
 spec/frontend/search/search_helper_spec.js         | 32 +++++++++++++
 7 files changed, 128 insertions(+), 23 deletions(-)
 create mode 100644 spec/frontend/search/search_helper_spec.js

diff --git a/content/assets/stylesheets/stylesheet.scss b/content/assets/stylesheets/stylesheet.scss
index 751c5b18..ebaa60bd 100644
--- a/content/assets/stylesheets/stylesheet.scss
+++ b/content/assets/stylesheets/stylesheet.scss
@@ -20,6 +20,11 @@ body {
   }
 }
 
+h2,
+h3,
+h4,
+h5,
+h6,
 :target {
   scroll-margin-top: $header-height + 1rem;
 }
diff --git a/content/frontend/search/components/lunr_results.vue b/content/frontend/search/components/lunr_results.vue
index 7d147127..f579938d 100644
--- a/content/frontend/search/components/lunr_results.vue
+++ b/content/frontend/search/components/lunr_results.vue
@@ -1,7 +1,7 @@
 <script>
 /* global lunr */
 import { GlSearchBoxByClick, GlLink } from '@gitlab/ui';
-import { getSearchParamsFromURL, updateURLParams } from '../search_helpers';
+import { getSearchParamsFromURL, updateURLParams, searchResultQueryParam } from '../search_helpers';
 import { isArchivesSite } from '../../default/environment';
 
 export default {
@@ -70,7 +70,10 @@ export default {
       Object.keys(this.results).forEach((key) => {
         const contentItem = this.contentMap.find(({ id }) => id === this.results[key].ref);
         this.results[key].title = contentItem.h1;
-        this.results[key].link = `/${this.results[key].ref}`;
+        this.results[key].link = `/${this.results[key].ref}${searchResultQueryParam(
+          this.query,
+          this.results[key].ref,
+        )}`;
       });
 
       // Rewrite links to include the version prefix if this is the archives site.
diff --git a/content/frontend/search/google.js b/content/frontend/search/google.js
index 153ef650..b13e6b49 100644
--- a/content/frontend/search/google.js
+++ b/content/frontend/search/google.js
@@ -1,8 +1,9 @@
 /* global Vue */
 import GoogleSearchForm from './components/google_search_form.vue';
-import { activateKeyboardShortcut } from './search_helpers';
+import { activateKeyboardShortcut, scrollToQuery } from './search_helpers';
 
 document.addEventListener('DOMContentLoaded', () => {
+  scrollToQuery();
   activateKeyboardShortcut();
 
   const { isHomepage } = document.querySelector('body').dataset;
diff --git a/content/frontend/search/lunrsearch.js b/content/frontend/search/lunrsearch.js
index 5ca9229a..15c215e9 100644
--- a/content/frontend/search/lunrsearch.js
+++ b/content/frontend/search/lunrsearch.js
@@ -1,26 +1,30 @@
 /* global Vue */
 import LunrResults from './components/lunr_results.vue';
 import SearchForm from './components/lunr_search_form.vue';
+import { activateKeyboardShortcut, scrollToQuery } from './search_helpers';
 
-// Search results page (/search)
 document.addEventListener('DOMContentLoaded', () => {
-  return new Vue({
-    el: '.js-lunrsearch',
-    render(createElement) {
-      return createElement(LunrResults);
-    },
-  });
-});
+  scrollToQuery();
+  activateKeyboardShortcut();
 
-// Homepage and interior navbar search forms
-document.addEventListener('DOMContentLoaded', () => {
-  return new Vue({
-    el: '.js-search-form',
-    components: {
-      SearchForm,
-    },
-    render(createElement) {
-      return createElement(SearchForm);
-    },
-  });
+  // Search results page (/search)
+  (() =>
+    new Vue({
+      el: '.js-lunrsearch',
+      render(createElement) {
+        return createElement(LunrResults);
+      },
+    }))();
+
+  // Homepage and interior navbar search forms
+  (() =>
+    new Vue({
+      el: '.js-search-form',
+      components: {
+        SearchForm,
+      },
+      render(createElement) {
+        return createElement(SearchForm);
+      },
+    }))();
 });
diff --git a/content/frontend/search/search_helpers.js b/content/frontend/search/search_helpers.js
index 744d7302..c4c22b7d 100644
--- a/content/frontend/search/search_helpers.js
+++ b/content/frontend/search/search_helpers.js
@@ -118,3 +118,58 @@ export const activateKeyboardShortcut = () => {
     document.querySelector('input[type="search"]').focus();
   });
 };
+
+/**
+ * Find the highest-level scrollable header that contains a given string.
+ *
+ * We need a regex here to match only if there are word boundaries or slashes.
+ * For example:
+ *  - "to" should match in "login to gitlab" but not "repository"
+ *  - "AI" should match in "AI/ML" but not "FAIL"
+ */
+export const findHighestHeader = (query) => {
+  const headings = document.querySelectorAll('h1, h2, h3, h4, h5, h6');
+
+  const regex = new RegExp(`(?<=^|\\s|\\/)${query}s?(?=$|\\s|\\/)`, 'gi');
+  const matches = Array.from(headings).filter((heading) => heading.textContent.match(regex));
+
+  if (matches.length) {
+    return matches.sort((a, b) => a.tagName.localeCompare(b.tagName))[0];
+  }
+
+  return null;
+};
+
+/**
+ * If a search query is in the URL parameters and a heading, scroll to it.
+ */
+export const scrollToQuery = () => {
+  const { qParam } = getSearchParamsFromURL();
+  if (!qParam) return;
+
+  const header = findHighestHeader(qParam);
+  if (header && header.tagName !== 'H1') {
+    header.scrollIntoView({ behavior: 'smooth' });
+  }
+};
+
+/**
+ * Generate a query string to be appended to search result links.
+ *
+ * This is used to limit which pages we run scrollToQuery() on.
+ */
+export const searchResultQueryParam = (query, link) => {
+  const pages = new Set(['/ee/ci/yaml/']);
+
+  // Check if the search result is included in the pages set.
+  let linkPath = '';
+  try {
+    const url = new URL(link); // Google results are full URLs
+    linkPath = url.pathname;
+  } catch {
+    linkPath = `/${link.replace('/index.html', '/')}`; // Lunr results are just paths
+  }
+
+  if (pages.has(linkPath)) return `?query=${query}`;
+  return '';
+};
diff --git a/content/frontend/services/google_search_api.js b/content/frontend/services/google_search_api.js
index c0b81b0e..e33fac77 100644
--- a/content/frontend/services/google_search_api.js
+++ b/content/frontend/services/google_search_api.js
@@ -1,5 +1,7 @@
 /* global GOOGLE_SEARCH_KEY */
 
+import { searchResultQueryParam } from '../search/search_helpers';
+
 export const GPS_ENDPOINT = 'https://www.googleapis.com/customsearch/v1/siterestrict?';
 export const GPS_ID = '97494f9fe316a426d';
 export const MAX_RESULTS_PER_PAGE = 10;
@@ -37,7 +39,10 @@ export const fetchResults = async (query, filters, pageNumber, numResults) => {
         .replace(' ...', '')
         .replaceAll('`', '')
         .trim(),
-      relativeLink: item.link.replace('https://docs.gitlab.com/', '/'),
+      relativeLink: `${item.link.replace('https://docs.gitlab.com/', '/')}${searchResultQueryParam(
+        query,
+        item.link,
+      )}`,
       breadcrumbs: item.pagemap.metatags[0]['gitlab-docs-breadcrumbs'] ?? '',
     }));
   }
diff --git a/spec/frontend/search/search_helper_spec.js b/spec/frontend/search/search_helper_spec.js
new file mode 100644
index 00000000..9fe01063
--- /dev/null
+++ b/spec/frontend/search/search_helper_spec.js
@@ -0,0 +1,32 @@
+/**
+ * @jest-environment jsdom
+ */
+
+import { findHighestHeader } from '../../../content/frontend/search/search_helpers';
+
+describe('frontend/search/search_helpers', () => {
+  beforeEach(() => {
+    // Create a mock DOM environment
+    document.body.innerHTML =
+      '<!DOCTYPE html><html><body><h2>login to gitlab</h2><h3>AI/ML</h3><h4>repository</h4></body></html>';
+  });
+
+  it('should find the correct scrollable header for query "to"', () => {
+    const result = findHighestHeader('to');
+    expect(result).toBeDefined();
+    expect(result.textContent).toBe('login to gitlab');
+    expect(result.tagName.toLowerCase()).toBe('h2');
+  });
+
+  it('should find the correct scrollable header for query "AI"', () => {
+    const result = findHighestHeader('AI');
+    expect(result).toBeDefined();
+    expect(result.textContent).toBe('AI/ML');
+    expect(result.tagName.toLowerCase()).toBe('h3');
+  });
+
+  it('should not find any scrollable header for query "FAIL"', () => {
+    const result = findHighestHeader('FAIL');
+    expect(result).toBeNull();
+  });
+});
-- 
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