fix: use placeholder as value when input is empty (#263)

Co-authored-by: Nate Moore <natemoo-re@users.noreply.github.com>

Author: jsparkdev

Diff for: .changeset/hot-turkeys-knock.md

@@ -0,0 +1,5 @@
+---
+"@clack/core": patch
+---
+
+Fixes an edge case for placeholder values. Previously, when pressing `enter` on an empty prompt, placeholder values would be ignored. Now, placeholder values are treated as the prompt value.

Diff for: packages/core/src/prompts/prompt.ts

@@ -205,6 +205,11 @@ export default class Prompt {
 		}
 
 		if (key?.name === 'return') {
+			if (!this.value && this.opts.placeholder) {
+				this.rl?.write(this.opts.placeholder);
+				this.emit('value', this.opts.placeholder);
+			}
+
 			if (this.opts.validate) {
 				const problem = this.opts.validate(this.value);
 				if (problem) {

Diff for: packages/prompts/src/index.test.ts

@@ -210,11 +210,11 @@ describe.each(['true', 'false'])('prompts (isCI = %s)', (isCI) => {
 
 			input.emit('keypress', '', { name: 'return' });
 
-			await result;
+			const value = await result;
 
 			expect(output.buffer).toMatchSnapshot();
-			// TODO (43081j): uncomment this when #263 is fixed
-			// expect(value).toBe('bar');
+
+			expect(value).toBe('bar');
 		});
 
 		test('<tab> applies placeholder', async () => {