Benchmark: Concat vs push.apply vs flat for larger arrays of arrays

Script Preparation code:

window.top.tests = {control:[], concat:[], concat2:[], spread:[], flat: []};
window.test = (new Array(10000)).fill(null);
window.arrays = (new Array(100)).fill(window.test);
window.cutoff = 5000;

Tests:

Control (for push)
window.top.tests.control = window.arrays.reduce((acc, arr) => { acc.push.apply(acc, arr); return acc; }, []); if (window.top.tests.control.length > window.cutoff) { window.top.tests.control = []; console.log('reset control'); }
Reduce Concat
window.top.tests.concat = window.arrays.reduce((acc, arr) => acc.concat(arr), []); if (window.top.tests.concat.length > window.cutoff) { window.top.tests.concat = []; console.log('reset concat'); }
Spread
window.top.tests.spread = window.arrays.reduce((acc, arr) => [...acc, ...arr], []); if (window.top.tests.spread.length > window.cutoff) { window.top.tests.spread = []; console.log('reset spread'); }
Flat
window.top.tests.flat = window.arrays.flat(); if (window.top.tests.flat.length > window.cutoff) { window.top.tests.flat = []; console.log('reset flat'); }
Array Concat
window.top.tests.concat2 = [].concat(...window.arrays); if (window.top.tests.concat2.length > window.cutoff) { window.top.tests.concat2 = []; console.log('reset concat2'); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Control (for push)
Reduce Concat
Spread
Flat
Array Concat

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

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 Edg/130.0.0.0

Browser/OS: Chrome 130 on Windows

View result in a separate tab

Array Concat

155/s

Control (for push)

34/s

Flat

21/s

Reduce Concat

3/s

Spread

1/s

View exact numbers

Test name	Executions per second
✓ Array Concat	155 Ops/sec
Control (for push)	34 Ops/sec
Flat	21 Ops/sec
Reduce Concat	3 Ops/sec
Spread	1 Ops/sec

Concat vs push.apply vs flat for larger arrays of arrays (version: 1)

Comparing the various ways to append to a large array again

Comparing performance of: `Control (for push) vs Reduce Concat vs Spread vs Flat vs Array Concat`

Created: one year ago by: Guest

Go to the latest result

Control (for push)

Reduce Concat

Spread

Flat

Array Concat

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Concat vs push.apply vs flat for larger arrays of arrays (version: 1)

Comparing the various ways to append to a large array again

Comparing performance of: Control (for push) vs Reduce Concat vs Spread vs Flat vs Array Concat

Created: one year ago by: Guest

Go to the latest result

Control (for push)

Reduce Concat

Spread

Flat

Array Concat

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `Control (for push) vs Reduce Concat vs Spread vs Flat vs Array Concat`