Run results for: replace vs substring vs slice from END

Test the performance of replace() vs substring() vs slice() when replacing a char at the beginning of a (in this case uri query-)string that may or may not be there. Added the combined brackets[ ] + substr() method, since it's always the first char we wan't to pop off. Inspired by https://jsperf.com/replace-or-substr. Note: could not get 'let' and 'const' to work. Well, too bad...

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 17_3 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) CriOS/123.0.6312.52 Mobile/15E148 Safari/604.1

Browser: Chrome Mobile iOS 123

Operating system: iOS 17.3

Device Platform: Mobile

Date tested: 7 months ago

Test name	Executions per second
substring	8409521.0 Ops/sec
replace inline regex	7098706.5 Ops/sec
replace compiled regex var	5721914.5 Ops/sec
slice	10427350.0 Ops/sec

Script Preparation code:

var strIn = 'https://www.data-xata.com/all-servers.html';
var strOut = '';
var regex = /\.html$/;

Tests:

substring
strOut = strIn.substring(0,strIn.length-5) + '.JS'
replace inline regex
strOut = strIn.replace(/\.html$/, '.JS');
replace compiled regex var
strOut = strIn.replace(regex, '.JS');
slice
strOut = strIn.slice(0,-5) + '.JS'

Run results for: replace vs substring vs slice from END

substring

replace inline regex

replace compiled regex var

slice