Run results for: 1d to 2d array - for i vs while splice

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.132 Safari/537.36

Browser: Chrome 76

Operating system: Mac OS X 10.14.6

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
for i; += 2	5205.8 Ops/sec
while splice	8000189.0 Ops/sec

Script Preparation code:

arr = [];
for (i=0; i<1024; i++) {
  arr.push(i); 
}

arr2 = [];
for (i=0; i<1024; i++) {
  arr2.push(i); 
}

Tests:

for i; += 2
var pairs = []; for (let i = 0; i < arr.length - 1; i += 2) { pairs.push([arr[i], arr[i + 1]]); }
while splice
var pairs = []; while(arr2.length) pairs.push(arr2.splice(0,2));