Run results for: For-of vs While - Random v1.2

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:60.0) Gecko/20100101 Firefox/60.0

Browser: Firefox 60

Operating system: Mac OS X 10.13

Device Platform: Desktop

Date tested: 6 years ago

Test name	Executions per second
forofreturn	1648627.0 Ops/sec
whileloopindex	13697160.0 Ops/sec

Script Preparation code:

var variants = [{ id: 1, weight: 1}, { id: 2, weight: 10 }, { id: 3, weight: 10 }, { id: 4, weight: 10 }, { id: 5, weight: 10 }];
var totalWeight = variants.reduce((sum, item) => sum + item.weight, 0);
var scores = Array.from({ length: 10 }).map(() => { Math.trunc(Math.random() * totalWeight) });

var forofreturn = (score) => {
  for (const variant of variants) {
    if (score < variant.weight) {
       return variant;
     }
     score -= variant.weight;
  }
}

var whileloopindex = (score) => {
  var index = 0;
  while (score > 0) {
    score -= variants[++index].weight;
  }

  return variants[index];
}

Tests:

forofreturn
forofreturn(scores[0]); forofreturn(scores[1]); forofreturn(scores[2]); forofreturn(scores[3]); forofreturn(scores[4]); forofreturn(scores[5]); forofreturn(scores[6]); forofreturn(scores[7]); forofreturn(scores[8]); forofreturn(scores[9]);
whileloopindex
whileloopindex(scores[0]); whileloopindex(scores[1]); whileloopindex(scores[2]); whileloopindex(scores[3]); whileloopindex(scores[4]); whileloopindex(scores[5]); whileloopindex(scores[6]); whileloopindex(scores[7]); whileloopindex(scores[8]); whileloopindex(scores[9]);