Closes #1487

Target Issue

Currently, the search engine indexes and displays results from older versions of the API (v3, v2) side-by-side with the current version (v4).

The Solution

This PR resolves the issue by upgrading to DocSearch v4 and implementing contextual search behavior using Algolia's optionalFilters.

By parsing the current URL path, the site now dynamically boosts the ranking of the documentation version the user is currently viewing.

• When on /lb4/ (or the root index), LoopBack 4 results are boosted.

• When on /lb3/, LoopBack 3 results are boosted.

• When on /lb2/, LoopBack 2 results are boosted.

This ensures the most relevant results appear first while still allowing users to search across the entire domain.

Changes Made

• DocSearch Upgrade: Bumped @docsearch/js and @docsearch/css from v3 to v4.

• Meta Tag Injection (_includes/head.html): Added Liquid templating to dynamically inject the <meta name="docsearch:version" content="..." /> tag based on the page's directory path.

Code snippet

{% if page.url contains '/lb4/' %}
  <meta name="docsearch:version" content="lb4" />
{% elsif page.url contains '/lb3/' %}
  <meta name="docsearch:version" content="lb3" />
{% elsif page.url contains '/lb2/' %}
  <meta name="docsearch:version" content="lb2" />
{% endif %}

• Contextual Search Boosting (docsearch initialization): Added logic to parse window.location.pathname to identify the user's current version, and passed that value into Algolia's searchParameters.

const path = window.location.pathname;
let currentVersion = 'lb4'; // Default version

if (path.includes('/lb3/')) {
    currentVersion = 'lb3';
} else if (path.includes('/lb2/')) {
    currentVersion = 'lb2';
}

// Inside the docsearch({}) config
searchParameters: {
    optionalFilters: [`version:${currentVersion}`]
}

Post-Merge Requirement

Action Required: Once this is merged and deployed, a manual re-crawl must be triggered in the Algolia Crawler Dashboard to index the new tags before the frontend optionalFilters will take effect.