Benchmark: Concat vs push(...) for large arrays of arrays

Script Preparation code:

window.top.tests = {control:[], concat:[], spread:[]};
window.test = (new Array(10)).fill(null);
window.arrays = (new Array(10)).fill(null).map(_ => window.test);
window.cutoff = 5000;

Tests:

Control (for push)
window.top.tests.control = window.arrays.reduce((acc, arr) => { acc.push(...arr); return acc; }, []); if (window.top.tests.control.length > window.cutoff) { window.top.tests.control = []; console.log('reset control'); }
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'); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Control (for push)
Concat
Spread

Fastest: N/A

Slowest: N/A

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Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36 OPR/68.0.3618.125

Browser/OS: Opera 68 on Windows

View result in a separate tab

Test name	Executions per second
Control (for push)	486194.4 Ops/sec
Concat	256130.0 Ops/sec
Spread	321717.5 Ops/sec

Concat vs push(...) for large arrays of arrays (version: 0)

Comparing the various ways to append to a large array

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

Created: 3 years ago by: Guest

Jump to the latest result

Control (for push)

Concat

Spread

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A