From a488df3f4c1267e8aef52e4ea7dc1545ba60ab9d Mon Sep 17 00:00:00 2001
From: Kevin Johnson <kevin@coolkev.com>
Date: Sun, 2 Feb 2020 09:02:30 -0500
Subject: [PATCH] Skip render if the output is unchanged (#45)

---
 index.js | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/index.js b/index.js
index 2c9bca4..5936db1 100644
--- a/index.js
+++ b/index.js
@@ -19,6 +19,8 @@ const main = (stream, options) => {
 	}, options);
 
 	let prevLineCount = 0;
+	let prevWidth = getWidth(stream);
+	let prevOut = '';
 
 	const render = (...args) => {
 		if (!options.showCursor) {
@@ -26,7 +28,14 @@ const main = (stream, options) => {
 		}
 
 		let out = args.join(' ') + '\n';
-		out = wrapAnsi(out, getWidth(stream), {
+		const width = getWidth(stream);
+		if (out === prevOut && prevWidth === width) {
+			return;
+		}
+
+		prevOut = out;
+		prevWidth = width;
+		out = wrapAnsi(out, width, {
 			trim: false,
 			hard: true,
 			wordWrap: false
@@ -37,10 +46,14 @@ const main = (stream, options) => {
 
 	render.clear = () => {
 		stream.write(ansiEscapes.eraseLines(prevLineCount));
+		prevOut = '';
+		prevWidth = getWidth(stream);
 		prevLineCount = 0;
 	};
 
 	render.done = () => {
+		prevOut = '';
+		prevWidth = getWidth(stream);
 		prevLineCount = 0;
 
 		if (!options.showCursor) {