Compare objects with variadic property set versus Map

maps-vs-objects.bench.js

const Benchmark = require('benchmark');

const suite = new Benchmark.Suite;

// Test data set size
const n = process.env.SET_SIZE || 100000;
// Megamorphic objects array
const objects = Array(n);
// Array of map instances
const maps = Array(n);

// Pregenerate objects
for (let i = 0; i < n; i++) {
    objects[i] = {};
    objects[i]['k' + i] = null;
    objects[i].x = i;

    maps[i] = new Map();
    maps[i].set('x', i);
    maps[i].set('k' + i, null);
}

function object(x) {
    return x.x + x.x;
}

function map(x) {
    return x.get('x') + x.get('x');
}

suite
.add('Objects', function() {
    for (var i = 0; i < n; i++) {
        object(objects[i]);
    }
})
.add('Maps', function() {
    for (var i = 0; i < n; i++) {
        map(maps[i]);
    }
})
.on('error', error => {
    console.error(error);
})
// add listeners
.on('cycle', function(event) {
  console.log(String(event.target));
})
.on('complete', function() {
  console.log('Fastest is ' + this.filter('fastest').map('name'));
})
.run();

result.txt

Objects x 46.53 ops/sec ±1.47% (55 runs sampled)
Maps x 126 ops/sec ±1.37% (67 runs sampled)