ref: cache getSitemapAsArray call to reduce redundant calls

[dcshzj]

Problem

We are calling getSitemapAsArray repeatedly, especially when generating a large collection page which uses getReferenceLinkHref on every item in the collection.

Solution

Breaking Changes

• Yes - this PR contains breaking changes
• No - this PR is backwards compatible

Improvements:

• Cache the result of getSitemapAsArray inside a new derived property inside the site-wide props.
• Refactor all usages of getReferenceLinkHref to use the new siteMapArray site-wide prop.

Before & After Screenshots

Screen.Recording.2026-03-18.at.14.12.54.mov

Tests

• Go to Isomer Studio and publish any site with a collection.
• Verify that the collection index page is the same as it was previously.
• Randomly sample two of the components that changed in this PR.
• For each of the component that changed, verify that the reference link is still resolving to the correct final permalink.

[Copilot]

Pull request overview

This PR refactors reference-link resolution to use a precomputed sitemap array (siteMapArray) instead of converting the sitemap tree on every call, and wires that derived data through IsomerSiteProps/rendering and UI components.

Changes:

• Update getReferenceLinkHref to accept sitemapArray: IsomerSitemap[] and migrate call sites to pass site.siteMapArray.
• Introduce siteMapArray as a derived site prop (IsomerDerivedSiteProps) and populate it in RenderEngine via getSitemapAsArray(site.siteMap).
• Update affected tests/stories/helpers to provide siteMapArray.

Reviewed changes

Copilot reviewed 30 out of 30 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
packages/components/src/utils/getTextAsHtml.ts	Passes site.siteMapArray into getReferenceLinkHref when rendering link marks.
packages/components/src/utils/getReferenceLinkHref.ts	Changes API to accept a precomputed sitemap array (and removes internal conversion).
packages/components/src/utils/tests/getReferenceLinkHref.test.ts	Updates tests to build and pass EXAMPLE_SITEMAP_ARRAY.
packages/components/src/types/site.ts	Adds IsomerDerivedSiteProps with required siteMapArray and composes it into IsomerSiteProps.
packages/components/src/templates/next/layouts/Collection/utils/processCollectionItems.ts	Passes site.siteMapArray into getReferenceLinkHref for collection item URLs.
packages/components/src/templates/next/components/internal/Vica/VicaWidget.tsx	Updates Vica widget asset/reference URL conversion to use siteMapArray.
packages/components/src/templates/next/components/internal/Navbar/Navbar.tsx	Updates navbar URL processing to use siteMapArray.
packages/components/src/templates/next/components/internal/Footer/Footer.tsx	Updates footer/social/contact/legal link resolution to use siteMapArray.
packages/components/src/templates/next/components/internal/ContentPageHeader/ContentPageHeader.tsx	Updates header button link resolution to use siteMapArray.
packages/components/src/templates/next/components/complex/*	Updates multiple complex components’ button/link href resolution to use siteMapArray.
packages/components/src/templates/next/components/complex/CollectionBlock/utils/getCollectionParent.ts	Switches collection parent lookup to site.siteMapArray.
packages/components/src/templates/next/components/complex/CollectionBlock/utils/tests/getCollectionParent.test.ts	Adds siteMapArray to fixtures (but currently not kept in sync with siteMap).
packages/components/src/templates/next/components/complex/CollectionBlock/utils/tests/getCollectionPages.test.ts	Adds siteMapArray to fixtures.
packages/components/src/stories/helpers/generateSiteConfig.ts	Adds siteMapArray to default story site config.
packages/components/src/interfaces/internal/Vica.ts	Updates Vica prop typing to require siteMapArray (instead of siteMap).
packages/components/src/engine/render.tsx	Derives siteMapArray inside RenderEngine from siteMap before rendering layouts.

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[datadog-opengovsg]

✅ Tests

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

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