Benchmark Object.keys().forEach vs for..in loop

benchmark-compare-keys-vs-loop-obj-iteration.spec.js

require("microtime");

const
    _ = require('lodash'),
    Benchmark = require('benchmark'),
    suite = new Benchmark.Suite,
    result = [],

    seedSize = 10000,
    seedData = Array(seedSize).fill().map(() => String(Math.round(Math.random() * seedSize))).reduce((obj, val) => {
        obj[val] = val;
        return obj;
    }, {});

suite
.add('iterating using object keys', function () {
    let arr = [];

    Object.keys(seedData).forEach((prop) => {
        arr.push(seedData[prop]);
    })
})
.add('iterating using guarded for-in loop', function () {
    let arr = [];

    for (let prop in seedData) {
        if (seedData.hasOwnProperty(prop)) {
            arr.push(seedData[prop]);
        }
    }
})
.add('iterating using un-guarded for-in loop', function () {
    let arr = [];

    for (let prop in seedData) {
        arr.push(seedData[prop]);
    }
})

.on('error', (event) => console.log(event.target.error))
.on('cycle', (event) => {
    console.log(String(event.target))
    result.push(event.target);
})
.on('complete', function () {
    console.log(`\nFastest is ${this.filter('fastest').map('name')}`);

    result
        .map((bench) => ({ name: bench.name, mean: bench.stats.mean}))
        .sort((a, b) => a.mean > b.mean)
        .forEach((bench,  index) => {
            console.log(` ${index+1}. ${bench.name}`);
        });
})
.run({ 'async': true });