Benchmark of Elm update function

index.js

// npm install benchmark
var bench = require('benchmark');

function updateOriginal(oldRecord, updatedFields)
{
	var newRecord = {};
	
    for (var key in oldRecord)
	{
		newRecord[key] = (key in updatedFields) ? updatedFields[key] : oldRecord[key];
	}
	
    return newRecord;
}

function updateNew(oldRecord, updatedFields)
{
    var newRecord = {};

    for (var key in oldRecord)
    {
        newRecord[key] = oldRecord[key];
    }

    for (var key in updatedFields) {
        newRecord[key] = updatedFields[key];
    }

    return newRecord;
}

function updateTypeof(oldRecord, updatedFields)
{
    var newRecord = {};

    for (var key in oldRecord)
    {
        var val = updatedFields[key];
        newRecord[key] = (typeof val !== 'undefined') ? val : oldRecord[key];
    }

    return newRecord;
}

var suite = new bench.Suite;

var baseObj = {
    name: "Robin",
    age: 27,
    hobbies: ["football", "chess", "programming"],
    male: true,
    occupation: "student",
    phoneNumber: 12345678,
    email: "[email protected]"
};

var updateObj = {
    age: 28
};

suite.add('original', function () {
    updateOriginal(baseObj, updateObj)
}).add('new', function () {
    updateNew(baseObj, updateObj);
}).add('typeof', function () {
    updateTypeof(baseObj, updateObj);
}).on('cycle', function (event) {
    console.log(String(event.target));
}).run();