Run results for: padLeft comparison

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36

Browser: Chrome 79

Operating system: Mac OS X 10.15.2

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
padLeft	149624.2 Ops/sec
slice	146550.9 Ops/sec
slice template literal	143562.7 Ops/sec
pad	115461.4 Ops/sec

HTML Preparation code:

<script>
const buffer = crypto.getRandomValues(new Uint8Array(16))

const z = '0'
const zz = '00'

function pad(pad, str) {
  if (typeof str === 'undefined') 
    return pad

  return (pad + str).slice(-pad.length)
}
</script>

Tests:

padLeft
for (let string = '', i = 0; i < buffer.length; i++) { string += buffer[i].toString(16).padStart(2, z) }
slice
for (let string = '', i = 0; i < buffer.length; i++) { string += (zz + buffer[i].toString(16)).slice(-2) }
slice template literal
for (let string = '', i = 0; i < buffer.length; i++) { string += `${zz}${buffer[i].toString(16)}`.slice(-2) }
pad
for (let string = '', i = 0; i < buffer.length; i++) { string += pad(zz, buffer[i].toString(16)) }

Run results for: padLeft comparison

padLeft

slice

slice template literal

pad