Run results for: Loops of loops VS. Manual Loops

Run details:

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:60.0) Gecko/20100101 Firefox/60.0

Browser: Firefox 60

Operating system: Ubuntu

Device Platform: Desktop

Date tested: 5 years ago

Test name	Executions per second
All finds in one loop	63.8 Ops/sec
Manual finds with multiple loops	358.4 Ops/sec

Script Preparation code:

var size = 1000000;
var arr = [];

for (var i=0; i < size; i++) {
  arr.push(i);
}

Tests:

All finds in one loop
var index1 = -1; var index2 = -1; var index3 = -1; var index4 = -1; var index5 = -1; for (var ii=0; ii < arr.length; ii++) { if (i === 23423) { index1 = i; } else if (i === 3453) { index2 = i; } else if (i === 9877) { index3 = i; } else if (i === 39248) { index4 = i; } else if (i === 908098) { index5 = i; } }
Manual finds with multiple loops
function findIndex(list, thing) { var foundIndex = -1; for (var i=0; i < list.length; i++) { if (i === thing) { foundIndex = i; } } return foundIndex; } var index1 = findIndex(arr, 23423); var index2 = findIndex(arr, 3453); var index3 = findIndex(arr, 9877); var index4 = findIndex(arr, 39248); var index5 = findIndex(arr, 908098);