Run results for: [find char positions] reg.exec vs for-loop vs for-indexOf

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36

Browser: Chrome 124

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
reg.exec	140010.5 Ops/sec
for-loop	50403.7 Ops/sec
for-indexOf	105460.1 Ops/sec

HTML Preparation code:

<script>

var _arr = (() => {
  const produce = (n) => new Array(n + 1).fill().map(() => `${Math.random()}`.slice(2)).join(']');
  const a0 = new Array(20).fill().map(() => produce(0));
  const a1 = new Array(20).fill().map(() => produce(1));
  const a2 = new Array(20).fill().map(() => produce(2));
  const a3 = new Array(20).fill().map(() => produce(3));
  const a4 = new Array(20).fill().map(() => produce(4));
  const arr = [].concat(a0).concat(a1).concat(a2).concat(a3).concat(a4);
  arr.sort(() => Math.random() - 0.5);
  return arr;
})();

function getPositions(path) {
  const positions = [];
  for (let i = 0; i < path.length; i++) {
    if (path[i] === ']') {
      positions.push(i);
    }
  }
  return positions;
}
                                  
                                  
function getPositionsIndexOf(path) {
  const positions = [];
  for (let i = 0; (i = path.indexOf(']', i)) >= 0; i++) {
    positions.push(i);
  }
  return positions;
}

</script>

Tests:

reg.exec
const arr = _arr; const len = arr.length; let r = 0; for (let i = 0; i < len; i++) { const reg = /\]/g; const positions = []; let match; const basic_path = arr[i]; while ((match = reg.exec(basic_path)) !== null) { positions.push(match.index); } r += positions.length; } window.tmp_r1 = r;
for-loop
const arr = _arr; const len = arr.length; let r = 0; for (let i = 0; i < len; i++) { const basic_path = arr[i]; const positions = getPositions(basic_path); r += positions.length; } window.tmp_r2 = r;
for-indexOf
const arr = _arr; const len = arr.length; let r = 0; for (let i = 0; i < len; i++) { const basic_path = arr[i]; const positions = getPositionsIndexOf(basic_path); r += positions.length; } window.tmp_r3 = r;