Run results for: slice vs subarray vs set - million elements

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36

Browser: Chrome 130

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

subarray direct

5.5M/s

subarray set

975/s

slice direct

866/s

subarray copy

699/s

slice set

448/s

slice copy

446/s

View exact numbers

Test name	Executions per second
✓ subarray direct	5,463,973 Ops/sec
subarray set	975 Ops/sec
slice direct	866 Ops/sec
subarray copy	699 Ops/sec
slice set	448 Ops/sec
slice copy	446 Ops/sec

Script Preparation code:

var data = new Array(1000000);

for (var i = 0; i < data.length; i++) {
  data[i] = i % 2 === 0 ? i : i + 0.5;
}
var f32 = new Float32Array(data);

Tests:

subarray direct
var copy = f32.subarray(0, 500000);
slice direct
var copy = f32.slice(0, 500000);
subarray copy
var copy = new Float32Array(f32.subarray(0, 500000));
slice copy
var copy = new Float32Array(f32.slice(0, 500000));
subarray set
var copy = new Float32Array(1000000).set(f32.subarray(0, 500000));
slice set
var copy = new Float32Array(1000000).set(f32.slice(0, 500000));