Run results for: New Object from Reduce vs. ForEach

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36

Browser: Chrome 114

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
Populate object via ForEach	33888.1 Ops/sec
Populate object via Reduce	17.1 Ops/sec

Script Preparation code:

var objects = Array.from(new Array(1000)).map((r, i) => ({
    id: `id-${i}`,
    val: i
}));
// Output should be
// { "id-0": 0, "id-1": 1, ... }

Tests:

Populate object via ForEach
var newMapFE = {}; objects.forEach(o => { newMapFE[o.id] = o.val })
Populate object via Reduce
objects.reduce((acc, item) => ({...acc, [item.id]: item.val}), {});

Run results for: New Object from Reduce vs. ForEach

Tests the difference in creating new objects by using reduce vs building up an object in a forEach function

Populate object via ForEach

Populate object via Reduce