Run results for: Different ways of iterating through an array, two elements at a time

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.127 Safari/537.36

Browser: Chrome 100

Operating system: Windows

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
++i, division and multiplication	10586.5 Ops/sec
++i and bit shift	10737.5 Ops/sec
i += 2	10829.2 Ops/sec
++i, ++i	10792.8 Ops/sec
++i, [++i]	10550.4 Ops/sec
[++i], [++i]	10578.4 Ops/sec
[i++], [i++]	10670.7 Ops/sec

Script Preparation code:

var a = [];
for (let i = 0; i < 1000; i++)
  a.push(i);

Tests:

++i, division and multiplication
for (let i = 0, l = a.length / 2; i < l; ++i) a[i * 2] + a[i * 2 + 1];
++i and bit shift
for (let i = 0, l = a.length >> 1; i < l; ++i) a[i << 1] + a[(i << 1) + 1];
i += 2
for (let i = 0, l = a.length - 1; i < l; i += 2) a[i] + a[i + 1];
++i, ++i
for (let i = 0, l = a.length - 1; i < l; ++i, ++i) a[i] + a[i + 1];
++i, [++i]
for (let i = 0, l = a.length - 1; i < l; ++i) a[i] + a[++i];
[++i], [++i]
for (let i = -1, l = a.length - 2; i < l;) a[++i] + a[++i];
[i++], [i++]
for (let i = 0, l = a.length - 1; i < l;) a[i++] + a[i++];