Run results for: char index vs charAt() vs slice() vs startsWith() vs RegExp Fixed - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/112.0

Browser: Firefox 112

Operating system: Linux

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
character index	122379392.0 Ops/sec
charAt()	92968456.0 Ops/sec
startsWith()	88312080.0 Ops/sec
slice()	67157704.0 Ops/sec
RegExp	25632930.0 Ops/sec
charCodeAt	85409032.0 Ops/sec
character index again	110157528.0 Ops/sec

Script Preparation code:

var str = '!foo bar baz';
var noop = Function.prototype;
var code = "!".charCodeAt(0)
var pattern = /^!/;

Tests:

character index
if (str[0] === '!') noop();
charAt()
if (str.charAt(0) === '!') noop();
startsWith()
if (str.startsWith('!')) noop();
slice()
if (str.slice(0, 1) === '!') noop();
RegExp
if (pattern.test(str)) noop();
charCodeAt
if(str.charCodeAt(0) === code) noop();
character index again
if (str[0] === '!') noop();