combobox: add use property

src/lib/Combobox.svelte

@@ -40,6 +40,7 @@
 		placeholder?: string;
 		notFoundMessage?: string;
 		class?: ClassValue | null | undefined;
+		use?: () => void;
 		onvalidate?: (e: InputValidatorEvent) => void;
 		onchange?: (item: ComboboxOption) => void;
 	}
@@ -57,6 +58,7 @@
 		placeholder,
 		notFoundMessage = 'No results found',
 		class: classValue,
+		use,
 		onvalidate,
 		onchange
 	}: Props = $props();
@@ -183,10 +185,24 @@
 		}
 	};
 
+	const conditionalUse = $derived(use ? use : () => {});
+
 	export const focus = () => {
 		searchInput?.focus();
 	};
 
+	export const setValueByString = (searchVal: string) => {
+		const item = options.find((opt) => opt.value === searchVal);
+		if (item) {
+			value = item;
+			searchValue = '';
+			open = false;
+			onchange?.(item);
+		} else {
+			console.warn(`Combobox: No option found with value "${searchVal}"`);
+		}
+	};
+
 	if (browser) {
 		// update picker position on window resize
 		window.addEventListener('resize', updatePickerRect);
@@ -444,6 +460,9 @@
 				searchValue = searchInput.value;
 				searching = true;
 			}}
+			use={() => {
+				conditionalUse();
+			}}
 		/>
 
 		{#if (value && value.infotext) || (highlighted && useHighlighted && highlighted.infotext)}