Run results for: Spacing a number every 3 digits

Run details:

User agent: Mozilla/5.0 (Linux; Android 7.0; SM-A510F Build/NRD90M) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.84 Mobile Safari/537.36

Browser: Chrome Mobile 62

Operating system: Android 7.0

Device Platform: Mobile

Date tested: 6 years ago

Test name	Executions per second
Using map+reverse+join	98579.5 Ops/sec
Using reduce	172883.1 Ops/sec

Tests:

Using map+reverse+join
const str = "1111111"; str.split("").reverse().map((x,i)=>{ if((i + 1) % 3 === 0){ return " "+x; } else { return x; } }).reverse().join("");
Using reduce
const str = "1111111"; str .split("") .reverse() .reduce((acc, cur, i) => { if (i === str.length - 1) return (cur + acc); return (((i + 1) % 3 === 0 ? ' ' : '') + cur + acc); } , "");