Run results for: Reduce with spread operator vs without on a large array

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser: Chrome 120

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Benchmark engine: Benchmark.js

reduce without spread

436/s

reduce with spread

51/s

View exact numbers

Test name	Executions per second
✓ reduce without spread	436 Ops/sec
reduce with spread	51 Ops/sec

Script Preparation code:

var array = new Array(10000).fill(1)

function withSpread(acc, item, index) {
    return {
        ...acc,
        [index]: {
            id: index,
            timestamp: new Date(new Date().getTime() + (index * 1000)),
            isOdd: index % 2 === 0,
            isEven: index % 2 !== 0
        }
    };
}

function withOutSpread(acc, item, index) {
    acc[index] = {
        id: index,
        timestamp: new Date(new Date().getTime() + (index * 1000)),
        isOdd: index % 2 === 0,
        isEven: index % 2 !== 0
    }
    return acc;
}

Tests:

reduce with spread
array.reduce(withSpread, {})
reduce without spread
array.reduce(withOutSpread, {})