fix(prompts): preserve falsy autocomplete initial values

.changeset/curly-mails-glow.md

@@ -0,0 +1,5 @@
+---
+"@clack/prompts": patch
+---
+
+Use an explicit undefined check when forwarding autocomplete initialValue so 0, false, and empty strings remain selectable instead of falling back to the first option.

packages/prompts/src/autocomplete.ts

@@ -129,7 +129,7 @@ export interface AutocompleteOptions<Value> extends AutocompleteSharedOptions<Va
 export const autocomplete = <Value>(opts: AutocompleteOptions<Value>) => {
 	const prompt = new AutocompletePrompt({
 		options: opts.options,
-		initialValue: opts.initialValue ? [opts.initialValue] : undefined,
+		initialValue: opts.initialValue !== undefined ? [opts.initialValue] : undefined,
 		initialUserInput: opts.initialUserInput,
 		placeholder: opts.placeholder,
 		completeOnTab: opts.completeOnTab,

packages/prompts/test/autocomplete.test.ts

@@ -185,6 +185,24 @@ describe('autocomplete', () => {
 		expect(output.buffer).toMatchSnapshot();
 	});
 
+	test('supports falsy initialValue values', async () => {
+		for (const initialValue of [0, false, '']) {
+			const input = new MockReadable();
+			const output = new MockWritable();
+			const result = autocomplete({
+				message: 'Select a value',
+				options: [{ value: 'other' }, { value: initialValue }],
+				initialValue,
+				input,
+				output,
+			});
+
+			input.emit('keypress', '', { name: 'return' });
+
+			expect(await result).toBe(initialValue);
+		}
+	});
+
 	test('can be aborted by a signal', async () => {
 		const controller = new AbortController();
 		const result = autocomplete({