Run results for: Array iter vs set iter (test order change)

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.66 Safari/537.36

Browser: Chrome 87

Operating system: Windows

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
native loop arr: few items	2355944.8 Ops/sec
for of set: few items	8464252.0 Ops/sec
for of arr: few items	8931765.0 Ops/sec
native iter set: few items	8418329.0 Ops/sec
for of arr: many items	763004.1 Ops/sec
for of set: many items	403391.9 Ops/sec
native loop arr: many items	9680.0 Ops/sec
native iter set: many items	400318.5 Ops/sec

Script Preparation code:

var fewItemArr = [1, 2, 3];
var fewItemSet = new Set(fewItemArr);
var manyItemArr = Array.from({ length: 1000 }, (_, i) => i);
var manyItemSet = new Set(manyItemArr);

Tests:

native loop arr: few items
let result = 0; for (let i = fewItemArr.length; i--;) { result += fewItemArr[i]; }
for of set: few items
let result = 0; for (const item of fewItemSet) { result += item; }
for of arr: few items
let result = 0; for (const item of fewItemArr) { result += item; }
native iter set: few items
let result = 0; let val = null; const iter = fewItemSet.values(); while (!(val = iter.next()).done) { result += val.value; }
for of arr: many items
let result = 0; for (const item of manyItemArr) { result += item; }
for of set: many items
let result = 0; for (const item of manyItemSet) { result += item; }
native loop arr: many items
let result = 0; for (let i = manyItemArr.length; i--;) { result += manyItemArr[i]; }
native iter set: many items
let result = 0; let val = null; const iter = manyItemSet.values(); while (!(val = iter.next()).done) { result += val.value; }

Run results for: Array iter vs set iter (test order change)

Iterate over an array vs iterating over a set.

native loop arr: few items

for of set: few items

for of arr: few items

native iter set: few items

for of arr: many items

for of set: many items

native loop arr: many items

native iter set: many items