Run results for: lodash/keyBy vs native reduce vs native with spread

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36

Browser: Chrome 95

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
lodash/keyBy	3147518.0 Ops/sec
keyBy with native reduce	4158270.0 Ops/sec
keyBy with forEach	2327896.0 Ops/sec
keyBy with for loop	4388728.0 Ops/sec
KeyBy with spread operator	949298.6 Ops/sec

HTML Preparation code:


<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Script Preparation code:

var data = [{
        name: 'pi',
        value: 3.14
    },
    {
        name: 'hundred',
        value: 100
    },
    {
        name: 'truthy',
        value: true
    },
    {
        name: 'falsy',
        value: false
    },
    {
        name: 'estring',
        value: '2.71828'
    },
];

var keyBy = (array, fn) => {
    return array.reduce((acc, value) => {
        acc[fn(value)] = value;
        return acc;
    }, {});
};

var keyBySpread = (array, fn) => {
    return array.reduce((acc, value) => ({
        ...acc,
        [fn(value)]: value
    }), {});
};

var keyByForEach = (array, fn) => {
    var acc = {};
    _.forEach(array, (value) => {
        acc[fn(value)] = value;
    });
    return acc;
};

var keyByForLoop = (array, fn) => {
    var acc = {};
    for (let i = 0; i < array.length; i++) {
        acc[fn(array[i])] = array[i];
    }
    return acc;
};

Tests:

lodash/keyBy
_.keyBy(data, (v) => v.name);
keyBy with native reduce
keyBy(data, (v) => v.name);
keyBy with forEach
keyByForEach(data, (v) => v.name);
keyBy with for loop
keyByForLoop(data, (v) => v.name);
KeyBy with spread operator
keyBySpread(data, (v) => v.name);

Run results for: lodash/keyBy vs native reduce vs native with spread

lodash/keyBy

keyBy with native reduce

keyBy with forEach

keyBy with for loop

KeyBy with spread operator