fix(print): prevent flickering by using debounce

package.json

@@ -104,6 +104,7 @@
     "cross-spawn": "6.0.5",
     "glob": "7.1.2",
     "keypress": "0.2.1",
+    "lodash.debounce": "4.0.8",
     "string-length": "2.0.0"
   },
   "scripts": {

src/store/index.js

@@ -1,9 +1,19 @@
 'use strict';
 /* eslint require-jsdoc: 0*/
+const debounce = require('lodash.debounce');
 const { program } = require('../commander');
 
 const cmdPrefix = cmd => `lerna-terminal${cmd ? `/${cmd}` : ''}~$ `;
 
+const print = debounce((value, stdin) => {
+	/* istanbul ignore next */
+	if (process.env.NODE_ENV !== 'ci' && process.env.NODE_ENV !== 'test') {
+		process.stdout.write('\x1Bc');
+	}
+	process.stdout.write(value);
+	process.stdout.write(stdin);
+}, 17);
+
 const state = {};
 const uiState = {
 	prefix: cmdPrefix(''),
@@ -20,12 +30,8 @@ const uiState = {
 			this.prefix = cmdPrefix('');
 		}
 		this.buffer = value;
-		/* istanbul ignore next */
-		if (process.env.NODE_ENV !== 'ci' && process.env.NODE_ENV !== 'test') {
-			process.stdout.write('\x1Bc');
-		}
-		process.stdout.write(value);
-		process.stdout.write(this.prefix + this.entered);
+
+		print(value, this.prefix + this.entered);
 	},
 	clearBuffer() {
 		this.buffer = '';

src/store/index.spec.js

@@ -24,28 +24,37 @@ describe('provideStore', () => {
 		uiState.onChange('lala');
 		expect(uiState.entered).toBe('lala');
 	});
-	it('getUiState().print', () => {
+	it('getUiState().print', done => {
 		const uiState = Object.assign({}, getUiState());
 		uiState.onChange('focus');
 		uiState.print('printValue');
-		expect(uiState.buffer).toBe('printValue');
-		expect(uiState.entered).toBe('focus');
-		expect(uiState.prefix).toBe('lerna-terminal~$ ');
+		setTimeout(() => {
+			expect(uiState.buffer).toBe('printValue');
+			expect(uiState.entered).toBe('focus');
+			expect(uiState.prefix).toBe('lerna-terminal~$ ');
+			done();
+		}, 20);
 	});
-	it('getUiState().print -> focused', () => {
+	it('getUiState().print -> focused', done => {
 		const uiState = Object.assign({}, getUiState(), {
 			focus: 'focusedPackage',
 		});
 		uiState.print('printValue');
-		expect(uiState.buffer).toBe('printValue');
-		expect(uiState.entered).toBe('');
-		expect(uiState.prefix).toBe('lerna-terminal/focusedPackage~$ ');
+		setTimeout(() => {
+			expect(uiState.buffer).toBe('printValue');
+			expect(uiState.entered).toBe('');
+			expect(uiState.prefix).toBe('lerna-terminal/focusedPackage~$ ');
+			done();
+		}, 20);
 	});
-	it('getUiState().clearBuffer', () => {
+	it('getUiState().clearBuffer', done => {
 		const uiState = Object.assign({}, getUiState());
 		uiState.print('printValue');
-		expect(uiState.buffer).toBe('printValue');
-		uiState.clearBuffer();
-		expect(uiState.buffer).toBe('');
+		setTimeout(() => {
+			expect(uiState.buffer).toBe('printValue');
+			uiState.clearBuffer();
+			expect(uiState.buffer).toBe('');
+			done();
+		}, 20);
 	});
 });