Improve performance (#49)

gtm-nayan · sindresorhus · web-flow · commit 840a5ea748d3 · 2023-05-28T16:53:40.000+07:00
Co-authored-by: Sindre Sorhus &lt;sindresorhus@gmail.com&gt;
diff --git a/index.js b/index.js
@@ -1,9 +1,14 @@
 import ansiRegex from 'ansi-regex';
 
+const regex = ansiRegex();
+
 export default function stripAnsi(string) {
 	if (typeof string !== 'string') {
 		throw new TypeError(`Expected a \`string\`, got \`${typeof string}\``);
 	}
 
-	return string.replace(ansiRegex(), '');
+	// Even though the regex is global, we don't need to reset the `.lastIndex`
+	// because unlike `.exec()` and `.test()`, `.replace()` does it automatically
+	// and doing it manually has a performance penalty.
+	return string.replace(regex, '');
 }

Original file line number	Diff line number	Diff line change
`@@ -1,9 +1,14 @@`
`1`	`1`	`import ansiRegex from 'ansi-regex';`
`2`	`2`
	`3`	`+const regex = ansiRegex();`
	`4`	`+`
`3`	`5`	`export default function stripAnsi(string) {`
`4`	`6`	`if (typeof string !== 'string') {`
`5`	`7`	throw new TypeError(`Expected a \`string\`, got \`${typeof string}\``);
`6`	`8`	`}`
`7`	`9`
`8`		`- return string.replace(ansiRegex(), '');`
	`10`	+ // Even though the regex is global, we don't need to reset the `.lastIndex`
	`11`	+ // because unlike `.exec()` and `.test()`, `.replace()` does it automatically
	`12`	`+ // and doing it manually has a performance penalty.`
	`13`	`+ return string.replace(regex, '');`
`9`	`14`	`}`