Fix virtual_scroll losing preloaded options after search (#998)

* Fix virtual_scroll losing preloaded options after search

When using virtual_scroll with preload: true, searching and then clearing
the search (or closing the dropdown) would show a mix of stale search
results and HTML-only options, losing all preloaded data. Two issues:

1. default_values is set on initialize before preload fires, so it only
   captures HTML <option> elements. When clearOptions(clearFilter) runs
   during a search, preloaded options are discarded.

2. Pagination state for the empty query is lost when getUrl() calls
   clearPagination() for a new search query, so virtual scroll stops
   working after clearing the search.

Fix: update default_values after the first loadCallback for the empty
query to include preloaded options, and save/restore the empty-query
pagination state when clearing search or closing the dropdown.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Put conditionals in brackets

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Nicolas CARPi <3043706+NicolasCARPi@users.noreply.github.com>

Author: 3 people

src/plugins/virtual_scroll/plugin.ts

@@ -28,6 +28,8 @@ export default function(this:TomSelect) {
 	var loading_more					= false;
 	var load_more_opt:HTMLElement;
 	var default_values: string[]		= [];
+	var default_values_loaded			= false;
+	var default_pagination:any;
 
 	if( !self.settings.shouldLoadMore ){
 
@@ -147,6 +149,16 @@ export default function(this:TomSelect) {
 
 		orig_loadCallback.call( self, options, optgroups);
 
+		// After the initial preload (empty query), update default_values to include
+		// preloaded options, not just the HTML <option> elements captured on initialize
+		if( !loading_more && !default_values_loaded ){
+			default_values_loaded = true;
+			if( self.lastValue === '' ){
+				default_values = Object.keys(self.options);
+				default_pagination = pagination[''];
+			}
+		}
+
 		loading_more = false;
 	});
 
@@ -191,6 +203,26 @@ export default function(this:TomSelect) {
 	});
 
 
+	// Restore preloaded options and pagination when clearing search
+	const restoreDefaults = ():void => {
+		if( !default_values_loaded ) {
+			return;
+		}
+		self.clearOptions(clearFilter);
+		if( default_pagination ) {
+			pagination[''] = default_pagination;
+		}
+	};
+
+	self.on('type',(query:string) => {
+		if( query === '' ){
+			restoreDefaults();
+			self.refreshOptions(false);
+		}
+	});
+
+	self.on('dropdown_close', restoreDefaults);
+
 	// add scroll listener and default templates
 	self.on('initialize',()=>{
 		default_values = Object.keys(self.options);

test/tests/plugins/virtual_scroll.js

@@ -164,6 +164,93 @@ describe('plugin: virtual_scroll', function() {
 	});
 
 
+	it_n('restore preloaded options after search is cleared',async ()=>{
+
+		var load_calls = 0;
+
+		var test = setup_test('<input>',{
+			plugins:['virtual_scroll'],
+			labelField: 'value',
+			valueField: 'value',
+			searchField: 'value',
+			preload: true,
+			loadThrottle: 1,
+			firstUrl: function(query){
+				return [query,0];
+			},
+			load: function(query, callback) {
+				load_calls++;
+				var url_params		= this.getUrl(query);
+				var data			= DataProvider(url_params[0],url_params[1]);
+				this.setNextUrl(query,[query,url_params[1]+1]);
+				callback(data.data);
+			}
+		});
+
+		// wait for preload to complete
+		await waitFor(100);
+		assert.equal( Object.keys(test.instance.options).length, 20, 'should have preloaded options');
+		assert.equal( load_calls, 1);
+
+		// search for "a"
+		await asyncClick(test.instance.control);
+		await asyncType('a');
+		await waitFor(100);
+		assert.equal( load_calls, 2);
+
+		// clear search - preloaded options should be restored
+		await asyncType('\b');
+		await waitFor(100);
+		assert.equal( Object.keys(test.instance.options).length, 20, 'should restore preloaded options after clearing search');
+
+		// verify none of the search results leaked through
+		var option_keys = Object.keys(test.instance.options);
+		var has_search_results = option_keys.some(k => k.startsWith('a-'));
+		assert.isFalse( has_search_results, 'should not contain stale search results');
+	});
+
+
+	it_n('virtual scroll works after clearing search',async ()=>{
+
+		var load_calls = 0;
+
+		var test = setup_test('<input>',{
+			plugins:['virtual_scroll'],
+			labelField: 'value',
+			valueField: 'value',
+			searchField: 'value',
+			preload: true,
+			loadThrottle: 1,
+			firstUrl: function(query){
+				return [query,0];
+			},
+			load: function(query, callback) {
+				load_calls++;
+				var url_params		= this.getUrl(query);
+				var data			= DataProvider(url_params[0],url_params[1]);
+				this.setNextUrl(query,[query,url_params[1]+1]);
+				callback(data.data);
+			}
+		});
+
+		// wait for preload
+		await waitFor(100);
+		assert.equal( load_calls, 1);
+
+		// search and clear
+		await asyncClick(test.instance.control);
+		await asyncType('a');
+		await waitFor(100);
+		await asyncType('\b');
+		await waitFor(100);
+
+		// scroll to bottom - should trigger loading more
+		test.instance.scroll(1000,'auto');
+		await waitFor(500);
+		assert.isAbove( Object.keys(test.instance.options).length, 20, 'should load more options after clearing search and scrolling');
+	});
+
+
 	it_n('keep default options',async ()=>{