Run results for: Custom Reduce vs Vanilla JS Reduce vs _lodash Reduce with Map

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser: Chrome 131

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
Vanilla JS Reduce on a Map	5.4 Ops/sec
Lodash Reduce on a Map	20.9 Ops/sec
Custom Reduce on a Map	104.4 Ops/sec

HTML Preparation code:


<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.min.js'></script>

Script Preparation code:

const reduce = (map, reducer, accumulator) => {
    let iter = map[Symbol.iterator]();
    let item;

    if (accumulator === undefined && (item = iter.next())) {
        if (item.done) return accumulator;
        accumulator = item.value[1];
    }

    while ((item = iter.next()) && !item.done)
        accumulator = reducer(accumulator, item.value[1], item.value[0]);
    return accumulator;
};

const randomMap = new Map(Array.from({length: 1000000}, (_, i) => [i, Math.floor(Math.random() * 100)]));
const sumValues = (a, b) => a + b;
const sumKeyValues = (a, b) => a + b[1];

Tests:

Vanilla JS Reduce on a Map
Array.from(randomMap).reduce(sumKeyValues, 0);
Lodash Reduce on a Map
_.reduce(_.toArray(randomMap), sumKeyValues, 0);
Custom Reduce on a Map
reduce(randomMap, sumValues, 0);

Run results for: Custom Reduce vs Vanilla JS Reduce vs _lodash Reduce with Map

Comparing the performance of the reduce functions on a Map

Vanilla JS Reduce on a Map

Lodash Reduce on a Map

Custom Reduce on a Map