Run results for: Map vs Map vs Foreach vs for - MeasureThat.net

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:63.0) Gecko/20100101 Firefox/63.0

Browser: Firefox 63

Operating system: Mac OS X 10.14

Device Platform: Desktop

Date tested: 5 years ago

Test name	Executions per second
Overwrite	77544.2 Ops/sec
Dont overwrite	110271.0 Ops/sec
forEach	371937.8 Ops/sec
for	135456.6 Ops/sec

Website performance monitoring

Script Preparation code:

var a = new Array(1000);
for (let i = 0; i < a.length; i++) {
  a[i] = {};
}

Tests:

Overwrite
a = a.map((row) => { row.checked = true; return row; });
Dont overwrite
const b = a.map((row) => { row.checked = true; return row; });
forEach
a.forEach((row) => { row.checked = true; });
for
for(let i=0; i<a.length; i++) { a[i].checked = true; }