Run results for: Lodash Object vs Array [immutable vs mutable] [object.keys vs object.entries]

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36

Browser: Chrome 81

Operating system: Mac OS X 10.15.5

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
obj immutable	4706.0 Ops/sec
arr immutable	4658.3 Ops/sec
obj mutable	91464.2 Ops/sec
arr mutable	154786.4 Ops/sec

HTML Preparation code:

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>

Script Preparation code:

window.arr = [];
window.obj = {};

for (var i = 0, len = 100; i < len; i++) {
    const src = {
        id: 'id-' + i
    };

    obj[src.id] = src;
    arr.push(src);
}

Tests:

obj immutable
_.reduce(obj, (acc, val, key) => { return { ...acc, [key]: val }; }, {});
arr immutable
_.reduce(arr, (acc, val) => { return { ...acc, [val.id]: val }; }, {});
obj mutable
_.reduce(obj, (acc, val, key) => { acc[key] = val; return acc; }, {});
arr mutable
_.reduce(arr, (acc, val) => { acc[val.id] = val; return acc; }, {});
obj keys
const keys = Object.keys(obj); _.reduce(keys, (acc, key) => { acc[key] = obj[key]; return acc; }, {});
obj entries
const pairs = Object.entries(obj); _.reduce(pairs, (acc, [key, val]) => { acc[key] = val; return acc; }, {});

Run results for: Lodash Object vs Array [immutable vs mutable] [object.keys vs object.entries]

obj immutable

arr immutable

obj mutable

arr mutable

obj keys

obj entries