Run results for: reduce concat vs flat vs concat spread vs reduce spread

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.3.1 Safari/605.1.15

Browser: Safari 17

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Benchmark engine: Benchmark.js

reduce + Array.prototype.concat

431K/s

concat(...)

211K/s

reduce spread

87K/s

Array.prototype.flat

13K/s

View exact numbers

Test name	Executions per second
✓ reduce + Array.prototype.concat	430,620 Ops/sec
concat(...)	210,557 Ops/sec
reduce spread	86,644 Ops/sec
Array.prototype.flat	12,876 Ops/sec

Script Preparation code:

var params = [
    [1, 2],
    ["hello", true, 7],
    Array(10000).fill(4),
];

Tests:

reduce + Array.prototype.concat
const x = params.reduce((acc, val) => acc.concat(val), []);
Array.prototype.flat
const x = params.flat(1);
concat(...)
const x = [].concat(...params)
reduce spread
const x = params.reduce((acc, val) => [...acc, ...val], []);