Run results for: RegEx.test vs. String.includes vs. String.startsWith

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser: Chrome 120

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Benchmark engine: Benchmark.js

string.includes

30.9M/s

string.startsWith

24.7M/s

startsWithJIT

14.3M/s

regex.test

12.2M/s

View exact numbers

Test name	Executions per second
✓ string.includes	30,936,690 Ops/sec
string.startsWith	24,669,022 Ops/sec
startsWithJIT	14,318,257 Ops/sec
regex.test	12,212,591 Ops/sec

Script Preparation code:

var string = "Hello world!";
var regex = /Hello/;

function startsWithJitGen(sequence) {
  const chain = []

  chain.push('(typeof value === \'string\')')
  chain.push(`(value.length >= ${sequence.length})`)

  for (let i = 0, il = sequence.length; i < il; ++i) {
    chain.push(`(value[${i}] === '${sequence[i]}')`)
  }

  const fnBody = 'return ' + chain.join(' && ')
  return new Function('value', fnBody)
}

var startsWithJIT = startsWithJitGen('Hello')

Tests:

regex.test
regex.test(string);
string.includes
string.includes("Hello");
string.startsWith
string.startsWith("Hello");
startsWithJIT
startsWithJIT(string)