# Preserve Advanced Search

Keeps the advanced search `a[]` query parameters attached to the facet slider
URLs that Facets builds server-side, so clicking a slider doesn't drop the
user's advanced search criteria.

Replaces the equivalent code that previously lived in individual themes
(`THEME.libraries.yml` + `THEME_preprocess_page()`).

## Install

    composer require roblib/preserve_advanced_search
    drush en preserve_advanced_search
    drush cr

Or copy this directory to `web/modules/custom/preserve_advanced_search` and
enable it as above.

## Scope

`hook_library_info_alter()` appends this module's library to the dependencies of
`facets_range_nouislider/facets_range_nouislider`. It therefore loads only on
pages that actually render a noUiSlider facet — not site-wide, and with no route
list to maintain per site.

Library info is cached, so run `drush cr` after deploying or the alter won't
take effect.

If a site configures its facets with the **Facets core** slider widget
(`facets_range_widget`) instead of `facets_range_nouislider`, add that
extension's library to the alter as well. Both submodules write to
`drupalSettings.facets.sliders`, so the JavaScript itself needs no change — only
the attachment point does.

## Notes

- Load order is guaranteed by the dependency: our script is loaded ahead of
  `slider.js`, so `Drupal.behaviors.preserveAdvancedSearchParams` is registered
  first and runs first. `facets_range_nouislider`'s `slider.js` is additionally
  marked `defer: true` while ours is not, and non-deferred scripts always
  execute before deferred ones — so the ordering holds twice over.
- `rebuildUrl()` is idempotent (it strips all `a[]` params before re-adding the
  current ones), so re-running on AJAX rebuilds is safe.
- The JS handles both `sliderSettings.url` and `sliderSettings.urls`. Range
  widgets collapse the parent's `urls` map into a single `url`
  (`RangeNoUiSliderWidget::build()`); single-handle widgets keep `urls`. Both
  branches are live — don't remove either.