Run results for: substring vs. slice vs. replace to remove string from end of input string

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:152.0) Gecko/20100101 Firefox/152.0

Browser: Firefox 152

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: 28 days ago

Using String.replace()

125/s

Using String.substring() with a magic number

97/s

Using String.substring() with a lastIndexOf() search

95/s

Using String.slice() without a pre-calculated suffix length

31/s

Using String.slice()

29/s

View exact numbers

Test name	Executions per second
✓ Using String.replace()	125 Ops/sec
Using String.substring() with a magic number	97 Ops/sec
Using String.substring() with a lastIndexOf() search	95 Ops/sec
Using String.slice() without a pre-calculated suffix length	31 Ops/sec
Using String.slice()	29 Ops/sec

Script Preparation code:

var numOfStrings = 100000
var suffix = 'TestStringHere'
var suffixLength = suffix.length
var negSuffixLength = suffixLength * -1
var testStrings = []

// Generate test string as a UUID + the suffix above.
function uuidv4() {
   return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g,
   function(c) {
      var uuid = Math.random() * 16 | 0, v = c == 'x' ? uuid : (uuid & 0x3 | 0x8);
      return uuid.toString(16);
   });
}

for (let i = 0; i < numOfStrings; i++) {
  testStrings.push(uuidv4() + suffix)
}

Tests: