Run results for: flatten - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:63.0) Gecko/20100101 Firefox/63.0

Browser: Firefox 63

Operating system: Windows

Device Platform: Desktop

Date tested: 5 years ago

Test name	Executions per second
1	1181280000.0 Ops/sec
2	10375310.0 Ops/sec

Script Preparation code:

const arr = [1, 2, [3, 4], 5, [6, [7, 8, [9, [10, 11], 12]]]];

Tests:

1
const flttn = (arr) => { if(!Array.isArray(arr)) return []; const fltn = (arr) => arr.reduce((acc, el) => Array.isArray(el) ? acc.concat(fltn(el)) : acc.concat(el), []); return fltn(arr); };
2
const scalar = v => !Array.isArray(v); const flatten = (deep, flat = []) => { if (deep.length === 0) return flat; let [head, ...tail] = deep; if (scalar(head)) { return flatten(tail, flat.concat(head)); } else { return flatten(tail, flat.concat(flatten(head))); } }