Run results for: for..of vs for vs flatMap

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36

Browser: Chrome 134

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

for

955/s

for of

811/s

flatMap

370/s

flatMap(n)

365/s

View exact numbers

Test name	Executions per second
✓ for	955 Ops/sec
for of	811 Ops/sec
flatMap	370 Ops/sec
flatMap(n)	365 Ops/sec

HTML Preparation code:

<!--your preparation HTML code goes here-->

Script Preparation code:

 var arr = [];
 var size = 1000;
 var size_n = 100;
 for (let i = 0; i < size; i++) {
     const innerData = [];
     for (let j = 0; j < 2; j++) { // Still 2 sub-arrays per data
         const subArray = [];
         for (let k = 0; k < size_n; k++) {
             subArray.push(i * size_n + j * size_n + k); // Unique values
         }
         innerData.push(subArray);
     }
     arr.push({
         data: innerData
     });
 }

Tests:

for
var result = []; for (let i = 0; i < arr.length; i++) { const data = arr[i].data; for (let j = 0; j < data.length; j++) { const subArray = data[j]; for (let k = 0; k < subArray.length; k++) { result.push(subArray[k]); } } }
for of
var result = []; for (let item of arr) { for (let subArray of item.data) { for (let element of subArray) { result.push(element); } } }
flatMap
arr.flatMap(x => x.data).flat()
flatMap(n)
arr.map(x => x.data).flat(2);