chore: Remove unused getBreakpointDeclarations function and any related code.

[jonrohan]

While removing feature flags, I was making note of some utils that aren't needed anymore. These weren't exported out of the package so there's no external use, and since we've refactored to CSS modules there's no internal use either.

Changelog

New

Changed

Removed

Remove unused getBreakpointDeclarations function and any related code.

Rollout strategy

• Patch release
• Minor release
• Major release; if selected, include a written rollout or migration plan
• None; if selected, include a brief description as to why

Testing & Reviewing

Merge checklist

• Added/updated tests
• Added/updated documentation
• Added/updated previews (Storybook)
• Changes are SSR compatible
• Tested in Chrome
• Tested in Firefox
• Tested in Safari
• Tested in Edge
• (GitHub staff only) Integration tests pass at github/github (Learn more about how to run integration tests)

[changeset-bot]

🦋 Changeset detected

Latest commit: d1c2cbd

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@primer/react	Patch

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[github-actions]

👋 Hi, this pull request contains changes to the source code that github/github depends on. If you are GitHub staff, we recommend testing these changes with github/github using the integration workflow. Thanks!

[Copilot]

Pull Request Overview

This PR removes an obsolete responsive styling utility and associated code/tests following the migration to CSS modules.

• Deleted breakpointHigher, breakpointLower, and mediaQueries from layout.ts
• Stripped out the getBreakpointDeclarations implementation and imports, leaving only unused helper functions
• Cleaned up PageHeader tests by removing deprecated media-query-based style assertions

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
packages/react/src/utils/layout.ts	Removed unused breakpoint helper functions and the mediaQueries export
packages/react/src/utils/getBreakpointDeclarations.ts	Removed the core implementation; left only two helper functions
packages/react/src/PageHeader/PageHeader.test.tsx	Dropped renderStyles tests and media-query imports
.changeset/tangy-facts-guess.md	Added changeset entry for the patch release

Comments suppressed due to low confidence (3)

packages/react/src/utils/getBreakpointDeclarations.ts:1

• [nitpick] After removing getBreakpointDeclarations, this file no longer matches its name. Consider renaming or relocating it to reflect its remaining helper functions, or deleting it if truly unused.

import type {ResponsiveValue} from '../hooks/useResponsiveValue'

packages/react/src/utils/getBreakpointDeclarations.ts:3

• The helper functions areAllValuesTheSame and haveRegularAndWideSameValue are no longer referenced. Remove these dead functions to clean up unused code.

export function areAllValuesTheSame(responsiveValue: ResponsiveValue<boolean | number | string>): boolean {

packages/react/src/PageHeader/PageHeader.test.tsx:3

• The MatchMediaMock import and corresponding matchmedia variable are no longer used in the tests—remove them to avoid dead code and potential linter warnings.

import MatchMediaMock from 'jest-matchmedia-mock'

[github-actions]

size-limit report 📦

Path	Size
packages/react/dist/browser.esm.js	94.42 KB (-0.01% 🔽)
packages/react/dist/browser.umd.js	94.48 KB (+0.01% 🔺)