luatnd/index.html

## index.html
<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8"/>
	<title>JS Object: Iteration performance</title>
	<script src="https://cdnjs.cloudflare.com/ajax/libs/benchmark/1.0.0/benchmark.min.js"></script>
	<script src="./suite.js"></script>
</head>
<body>
	<h1>Open the console to view the results</h1>
	<h2><code>cmd + alt + j</code> or <code>ctrl + alt + j</code></h2>
</body>
</html>

## suite.js
"use strict";

(function (factory) {
	if (typeof Benchmark !== "undefined") {
		factory(Benchmark);
	} else {
		factory(require("benchmark"));
	}
})(function (Benchmark) {
	var suite = new Benchmark.Suite;

	Benchmark.prototype.setup = function () {
		var i,
		    value,
		    length,
		    exampleArray = [],
		    exampleObject = {},
		    context = exampleArray;


		for (i = 0; i < 20000; i++) {
		    const r = Math.random();
		    exampleArray[i] = r;
		    exampleObject[i] = r;
		}

		function readValue(val) {
		    let a = val;
		}
	};


	suite.add("exampleArray.forEach(readValue);", function () {
		exampleArray.forEach(readValue);
	});

	suite.add("for (i = 0, c = exampleArray.length; i < c; i++) {", function () {
		for (i = 0, c = exampleArray.length; i < c; i++) {
		    readValue(exampleArray[i]);
		}
	});

	suite.add("for (value of exampleArray) {", function () {
		for (value of exampleArray) {
		    readValue(value);
		}
	});

	suite.add("for (let i in exampleArray) {", function () {
		for (let i in exampleArray) {
		    readValue(exampleArray[i]);
		}
	});

	suite.add("for (let i in exampleObject) {", function () {
		for (let i in exampleObject) {
		  readValue(exampleObject[i])
		}
	});

	suite.add("const keys = Object.keys(exampleObject);", function () {
		const keys = Object.keys(exampleObject);
		 for (let i = 0, c = keys.length; i < c; i++) {
		    const k = keys[i];
		    const v = exampleObject[k];
		  }
	});

	suite.on("cycle", function (evt) {
		console.log(" - " + evt.target);
	});

	suite.on("complete", function (evt) {
		console.log(new Array(30).join("-"));

		var results = evt.currentTarget.sort(function (a, b) {
			return b.hz - a.hz;
		});

		results.forEach(function (item) {
			console.log((idx + 1) + ". " + item);
		});
	});

	console.log("JS Object: Iteration performance");
	console.log(new Array(30).join("-"));
	suite.run();
});
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8"/>
	<title>JS Object: Iteration performance</title>
	<script src="https://cdnjs.cloudflare.com/ajax/libs/benchmark/1.0.0/benchmark.min.js"></script>
	<script src="./suite.js"></script>
	</head>
	<body>
	<h1>Open the console to view the results</h1>
	<h2><code>cmd + alt + j</code> or <code>ctrl + alt + j</code></h2>
	</body>
	</html>
	"use strict";

	(function (factory) {
	if (typeof Benchmark !== "undefined") {
	factory(Benchmark);
	} else {
	factory(require("benchmark"));
	}
	})(function (Benchmark) {
	var suite = new Benchmark.Suite;

	Benchmark.prototype.setup = function () {
	var i,
	value,
	length,
	exampleArray = [],
	exampleObject = {},
	context = exampleArray;


	for (i = 0; i < 20000; i++) {
	const r = Math.random();
	exampleArray[i] = r;
	exampleObject[i] = r;
	}

	function readValue(val) {
	let a = val;
	}
	};


	suite.add("exampleArray.forEach(readValue);", function () {
	exampleArray.forEach(readValue);
	});

	suite.add("for (i = 0, c = exampleArray.length; i < c; i++) {", function () {
	for (i = 0, c = exampleArray.length; i < c; i++) {
	readValue(exampleArray[i]);
	}
	});

	suite.add("for (value of exampleArray) {", function () {
	for (value of exampleArray) {
	readValue(value);
	}
	});

	suite.add("for (let i in exampleArray) {", function () {
	for (let i in exampleArray) {
	readValue(exampleArray[i]);
	}
	});

	suite.add("for (let i in exampleObject) {", function () {
	for (let i in exampleObject) {
	readValue(exampleObject[i])
	}
	});

	suite.add("const keys = Object.keys(exampleObject);", function () {
	const keys = Object.keys(exampleObject);
	for (let i = 0, c = keys.length; i < c; i++) {
	const k = keys[i];
	const v = exampleObject[k];
	}
	});

	suite.on("cycle", function (evt) {
	console.log(" - " + evt.target);
	});

	suite.on("complete", function (evt) {
	console.log(new Array(30).join("-"));

	var results = evt.currentTarget.sort(function (a, b) {
	return b.hz - a.hz;
	});

	results.forEach(function (item) {
	console.log((idx + 1) + ". " + item);
	});
	});

	console.log("JS Object: Iteration performance");
	console.log(new Array(30).join("-"));
	suite.run();
	});