feature(instant-results): add filters for labels, options, components, and config

[faisalahammad]

Summary

This PR adds more filters to the Instant Results feature so developers can customize facet labels, facet options, individual components, and the front-end configuration object. It addresses the customization gaps described in #3975.

Fixes #3975

Changes

assets/js/api-search/index.js

Before:

setResults(response);

After:

const filteredResponse = applyFilters('ep.InstantResults.response', response);

setResults(filteredResponse || response);

Why: allows third-party code to modify the search results response before it is passed to the React state, with a fallback in case a filter returns a falsy value.

assets/js/instant-results/components/facets/facet.js

Before: facets received the label prop directly.

After: the label is passed through ep.InstantResults.filter.label with the facet name, type, and post types so all facet labels can be customized from one filter.

Why: gives developers a single hook for changing facet labels without editing component internals.

assets/js/instant-results/components/facets/post-type-facet.js

Before:

const options = useMemo(() => buckets.reduce(reduceOptions, []), [buckets, reduceOptions]);

After: reduced options are passed through ep.InstantResults.filter.postType.options before being rendered.

Why: lets developers reorder, remove, or relabel post type options.

assets/js/instant-results/components/facets/price-range-facet.js

Before: the slider min/max were taken directly from aggregations.

After: the min/max values are passed through ep.InstantResults.filter.priceRange.options as { min, max }.

Why: allows the price range bounds to be adjusted by third-party code.

assets/js/instant-results/components/results/did-you-mean.js and assets/js/instant-results/components/tools/sort.js

Before: components were returned directly.

After: components are assigned to a variable and returned through ep.InstantResults.component.didYouMean and ep.InstantResults.component.sort respectively.

Why: follows the same pattern already used for ep.InstantResults.Result and ep.InstantResults.Pagination so components can be wrapped or replaced.

includes/classes/Feature/InstantResults/InstantResults.php

Before: the localized epInstantResults config was passed directly to wp_localize_script.

After: the config is built into a variable, filtered through ep_instant_results_config, and then passed to wp_localize_script.

Why: provides a PHP-side hook for the entire front-end configuration object.

Testing

Test 1: Facet label filter

1. Add a JS filter on ep.InstantResults.filter.label to rename a taxonomy facet.
2. Open Instant Results and view the sidebar.

Result: the facet label is updated.

Test 2: Post type options filter

1. Add a JS filter on ep.InstantResults.filter.postType.options to transform option labels.
2. Open Instant Results and expand the post type facet.

Result: the option labels reflect the filter output.

Test 3: PHP config filter

1. Add a PHP filter on ep_instant_results_config to change a value.
2. Load the page and inspect window.epInstantResults.

Result: the modified value is present in the front-end config.

Notes

• npm run lint-js passes for the changed JS files.
• composer run lint reports only pre-existing failures in other test files; InstantResults.php is clean.
• vendor/bin/phpunit --filter TestInstantResults passes except for an unrelated pre-existing quote mismatch in test_requirements_status.
• CodeRabbit review passed with no actionable findings.