Discard stdin by default (#112)

Co-authored-by: Sindre Sorhus <[email protected]>

example.js

@@ -3,31 +3,42 @@ const chalk = require('chalk');
 const Ora = require('.');
 
 const spinner = new Ora({
+	discardStdin: false,
+	text: 'Loading unicorns, not discarding stdin',
+	spinner: process.argv[2]
+});
+
+const spinnerDiscardingStdin = new Ora({
 	text: 'Loading unicorns',
 	spinner: process.argv[2]
 });
 
-spinner.start();
+spinnerDiscardingStdin.start();
+
+setTimeout(() => {
+	spinnerDiscardingStdin.succeed();
+	spinner.start();
+}, 3000);
 
 setTimeout(() => {
 	spinner.color = 'yellow';
 	spinner.text = `Loading ${chalk.red('rainbows')}`;
-}, 1000);
+}, 4000);
 
 setTimeout(() => {
 	spinner.color = 'green';
 	spinner.indent = 2;
 	spinner.text = 'Loading with indent';
-}, 2000);
+}, 5000);
 
 setTimeout(() => {
 	spinner.indent = 0;
 	spinner.spinner = 'moon';
 	spinner.text = 'Loading with different spinners';
-}, 3000);
+}, 6000);
 
 setTimeout(() => {
 	spinner.succeed();
-}, 4000);
+}, 7000);
 
 // $ node example.js nameOfSpinner

index.d.ts

@@ -89,6 +89,13 @@ declare namespace ora {
 		Note that `{isEnabled: false}` doesn't mean it won't output anything. It just means it won't output the spinner, colors, and other ansi escape codes. It will still log text.
 		*/
 		readonly isEnabled?: boolean;
+
+		/**
+		Discard stdin input (except Ctrl+C) while running if it's TTY. This prevents the spinner from twitching on input, outputting broken lines on `Enter` key presses, and prevents buffering of input while the spinner is running.
+
+		@default true
+		*/
+		readonly discardStdin?: boolean;
 	}
 
 	interface PersistOptions {

index.js

@@ -10,6 +10,10 @@ const isInteractive = require('is-interactive');
 const TEXT = Symbol('text');
 const PREFIX_TEXT = Symbol('prefixText');
 
+const noop = () => {};
+
+const ASCII_ETX_CODE = 0x03; // Ctrl+C emits this code
+
 class Ora {
 	constructor(options) {
 		if (typeof options === 'string') {
@@ -21,7 +25,8 @@ class Ora {
 		this.options = Object.assign({
 			text: '',
 			color: 'cyan',
-			stream: process.stderr
+			stream: process.stderr,
+			discardStdin: true
 		}, options);
 
 		this.spinner = this.options.spinner;
@@ -38,6 +43,7 @@ class Ora {
 		this.prefixText = this.options.prefixText;
 		this.linesToClear = 0;
 		this.indent = this.options.indent;
+		this.discardStdin = this.options.discardStdin;
 	}
 
 	get indent() {
@@ -171,6 +177,10 @@ class Ora {
 			cliCursor.hide(this.stream);
 		}
 
+		if (this.discardStdin && process.stdin.isTTY) {
+			this.startDiscardingStdin();
+		}
+
 		this.render();
 		this.id = setInterval(this.render.bind(this), this.interval);
 
@@ -190,9 +200,55 @@ class Ora {
 			cliCursor.show(this.stream);
 		}
 
+		if (this.discardStdin && process.stdin.isTTY) {
+			this.stopDiscardingStdin();
+		}
+
 		return this;
 	}
 
+	startDiscardingStdin() {
+		const {stdin} = process;
+
+		this._stdinOldRawMode = stdin.isRaw;
+		this._stdinOldEmit = stdin.emit;
+		this._stdinOldEmitOwnProperty = Object.prototype.hasOwnProperty.call(stdin, 'emit');
+
+		stdin.setRawMode(true);
+		stdin.on('data', noop);
+
+		const self = this;
+		stdin.emit = function (event, data, ...args) {
+			if (event === 'data' && data.includes(ASCII_ETX_CODE)) {
+				process.emit('SIGINT');
+			}
+
+			self._stdinOldEmit.apply(this, [event, data, ...args]);
+		};
+	}
+
+	stopDiscardingStdin() {
+		if (this._stdinOldEmit !== undefined) {
+			const {stdin} = process;
+			stdin.setRawMode(this._stdinOldRawMode);
+			stdin.removeListener('data', noop);
+
+			if (stdin.listenerCount('data') === 0) {
+				stdin.pause();
+			}
+
+			if (this._stdinOldEmitOwnProperty) {
+				stdin.emit = this._stdinOldEmit;
+			} else {
+				delete stdin.emit;
+			}
+
+			this._stdinOldRawMode = undefined;
+			this._stdinOldEmit = undefined;
+			this._stdinOldEmitOwnProperty = undefined;
+		}
+	}
+
 	succeed(text) {
 		return this.stopAndPersist({symbol: logSymbols.success, text});
 	}

index.test-d.ts

@@ -15,6 +15,7 @@ ora({indent: 1});
 ora({interval: 80});
 ora({stream: new PassThroughStream()});
 ora({isEnabled: true});
+ora({discardStdin: true});
 
 spinner.color = 'yellow';
 spinner.text = 'Loading rainbows';

readme.md

@@ -117,6 +117,13 @@ Force enable/disable the spinner. If not specified, the spinner will be enabled
 
 Note that `{isEnabled: false}` doesn't mean it won't output anything. It just means it won't output the spinner, colors, and other ansi escape codes. It will still log text.
 
+##### discardStdin
+
+Type: `boolean`<br>
+Default: `true`
+
+Discard stdin input (except Ctrl+C) while running if it's TTY. This prevents the spinner from twitching on input, outputting broken lines on <kbd>Enter</kbd> key presses, and prevents buffering of input while the spinner is running.
+
 ### Instance
 
 #### .start(text?)