feat(@clack/prompts): adapt spinner to CI environment

.changeset/thin-moose-tease.md

@@ -0,0 +1,5 @@
+---
+'@clack/prompts': patch
+---
+
+Adapts `spinner` output for static CI environments

examples/basic/package.json

@@ -10,7 +10,8 @@
   },
   "scripts": {
     "start": "jiti ./index.ts",
-    "spinner": "jiti ./spinner.ts"
+    "spinner": "jiti ./spinner.ts",
+    "spinner-ci": "npx cross-env CI=\"true\" jiti ./spinner-ci.ts"
   },
   "devDependencies": {
     "jiti": "^1.17.0"

examples/basic/spinner-ci.ts

@@ -0,0 +1,36 @@
+/**
+ * This example addresses a issue reported in GitHub Actions where `spinner` was excessively writing messages,
+ * leading to confusion and cluttered output.
+ * To enhance the CI workflow and provide a smoother experience,
+ * the following changes have been made only for CI environment:
+ * - Messages will now only be written when a `spinner` method is called and the message updated, preventing unnecessary message repetition.
+ * - There will be no loading dots animation, instead it will be always `...`
+ * - Instead of erase the previous message, action that is blocked during CI, it will just write a new one.
+ *
+ * Issue: https://github.com/natemoo-re/clack/issues/168
+ */
+import * as p from '@clack/prompts';
+
+const s = p.spinner();
+let progress = 0;
+let counter = 0;
+let loop: NodeJS.Timer;
+
+p.intro('Running spinner in CI environment');
+s.start('spinner.start');
+new Promise((resolve) => {
+	loop = setInterval(() => {
+		if (progress % 1000 === 0) {
+			counter++;
+		}
+		progress += 100;
+		s.message(`spinner.message [${counter}]`);
+		if (counter > 6) {
+			clearInterval(loop);
+			resolve(true);
+		}
+	}, 100);
+}).then(() => {
+	s.stop('spinner.stop');
+	p.outro('Done');
+});

examples/basic/spinner.ts

@@ -3,7 +3,7 @@ import * as p from '@clack/prompts';
 p.intro('spinner start...');
 
 const spin = p.spinner();
-const total = 10000;
+const total = 6000;
 let progress = 0;
 spin.start();
 

packages/prompts/src/index.ts

@@ -643,11 +643,13 @@ export const log = {
 export const spinner = () => {
 	const frames = unicode ? ['◒', '◐', '◓', '◑'] : ['•', 'o', 'O', '0'];
 	const delay = unicode ? 80 : 120;
+	const isCI = process.env.CI === 'true';
 
 	let unblock: () => void;
 	let loop: NodeJS.Timeout;
 	let isSpinnerActive = false;
 	let _message = '';
+	let _prevMessage: string | undefined = undefined;
 
 	const handleExit = (code: number) => {
 		const msg = code > 1 ? 'Something went wrong' : 'Canceled';
@@ -676,44 +678,59 @@ export const spinner = () => {
 		process.removeListener('exit', handleExit);
 	};
 
+
+	const clearPrevMessage = () => {
+		if (_prevMessage === undefined) return;
+		if (isCI) process.stdout.write('\n');
+		const prevLines = _prevMessage.split('\n');
+		process.stdout.write(cursor.move(-999, prevLines.length - 1));
+		process.stdout.write(erase.down(prevLines.length));
+	};
+
+	const parseMessage = (msg: string): string => {
+		return msg.replace(/\.+$/, '');
+	};
+
 	const start = (msg = ''): void => {
 		isSpinnerActive = true;
 		unblock = block();
-		_message = msg.replace(/\.+$/, '');
+		_message = parseMessage(msg);
 		process.stdout.write(`${color.gray(S_BAR)}\n`);
 		let frameIndex = 0;
 		let dotsTimer = 0;
 		registerHooks();
 		loop = setInterval(() => {
+			if (isCI && _message === _prevMessage) {
+				return;
+			}
+			clearPrevMessage();
+			_prevMessage = _message;
 			const frame = color.magenta(frames[frameIndex]);
-			const loadingDots = '.'.repeat(Math.floor(dotsTimer)).slice(0, 3);
-			process.stdout.write(cursor.move(-999, 0));
-			process.stdout.write(erase.down(1));
+			const loadingDots = isCI ? '...' : '.'.repeat(Math.floor(dotsTimer)).slice(0, 3);
 			process.stdout.write(`${frame}  ${_message}${loadingDots}`);
 			frameIndex = frameIndex + 1 < frames.length ? frameIndex + 1 : 0;
 			dotsTimer = dotsTimer < frames.length ? dotsTimer + 0.125 : 0;
 		}, delay);
 	};
 
 	const stop = (msg = '', code = 0): void => {
-		_message = msg ?? _message;
 		isSpinnerActive = false;
 		clearInterval(loop);
+		clearPrevMessage();
 		const step =
 			code === 0
 				? color.green(S_STEP_SUBMIT)
 				: code === 1
 					? color.red(S_STEP_CANCEL)
 					: color.red(S_STEP_ERROR);
-		process.stdout.write(cursor.move(-999, 0));
-		process.stdout.write(erase.down(1));
+		_message = parseMessage(msg ?? _message);
 		process.stdout.write(`${step}  ${_message}\n`);
 		clearHooks();
 		unblock();
 	};
 
 	const message = (msg = ''): void => {
-		_message = msg ?? _message;
+		_message = parseMessage(msg ?? _message);
 	};
 
 	return {