Run results for: Reduce with spread operator vs without on a large array 2

Run details:

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Mobile Safari/537.36

Browser: Chrome Mobile 122

Operating system: Android

Device Platform: Mobile

Date tested: 2 years ago

Benchmark engine: Benchmark.js

reduce without spread

118/s

reduce with spread

37/s

View exact numbers

Test name	Executions per second
✓ reduce without spread	118 Ops/sec
reduce with spread	37 Ops/sec

Script Preparation code:

var array = new Array(10000).fill(1)

function withSpread(item, index) {
    return {
        [`group${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
Object.assign({}, ...array.map(withSpread))
reduce without spread
array.reduce(withOutSpread, {})