Run results for: slice vs moving array vs reduce

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.92 Safari/537.36

Browser: Chrome 81

Operating system: Windows

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
slice	34454.7 Ops/sec
moving array	30739.6 Ops/sec

Script Preparation code:

var arr = [];
for (var i = 0; i < 100; i++) {
  arr.push(i);
}

Tests:

moving array
var range = []; for (var i = 0; i < arr.length; i++) { range.push(arr[i]); if (range.length > 9) { range.splice(0, 1); } if (i > 8) {var avg = range.reduce(function(accu, next){ return accu + next ;}) / 9;} }
slice
for (var i = 0; i < arr.length; i++) { if (i < 9) continue; var range = arr.slice(i, i + 9); var avg = range.reduce(function(accu, next){ return accu + next ;}) / 9; }
reduce
var sum = 0; for (var i = 0; i < arr.length; i++) { sum += arr[i]; if (i > 8) { sum -= arr[i - 9]; } if (i > 8) {var avg = sum / 9;} }