Run results for: flatten merge array : reduce VS Object.assign

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36

Browser: Chrome 122

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Object.assign

2K/s

Reduce

2K/s

View exact numbers

Test name	Executions per second
✓ Object.assign	1,698 Ops/sec
Reduce	1,671 Ops/sec

Script Preparation code:

function createArray(k, propsCount) {
    const arr = []
    for (let i = 0; i < propsCount; i += 1) {
        arr.push({
            id: k * i,
            active: i % 5 === 0
        })
    }
    return arr.reduce((obj, u) =>  ({...obj, [u.id]: u}), {})
}

var pages = [createArray(1, 1000),createArray(10,1000),createArray(100,1000)]

Tests:

Reduce
allusers = pages.reduce((store, page) => ({...store, ...page}), {})
Object.assign
allUsers = Object.assign({}, ...pages.flat())