anilanar/index.html

## index.html
<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8"/>
	<title>Object structure #jsbench #jsperf</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 () {
		function createObj1(x) {
		    if (x === undefined) {
		        var obj = {};
		        obj.a = 1;
		        return obj;
		    }
		    return {};
		}
		function createObj2(x) {
		    return {
		        a: x === undefined ? undefined : 1
		    };
		}
	};


	suite.add("var arr = [];", function () {
		var arr = [];
		for (var i = 0; i < 100; i++) {
		    arr.push(createObj1(i & 1 ? i : undefined));
		}
		arr.splice(20, 60);
		var count = 0;
		for (var i = 0; i < 40; i++) {
		    if (arr[i].a !== undefined) {
		        count++;
		    }
		}
	});

	suite.add("var arr = [];", function () {
		var arr = [];
		for (var i = 0; i < 100; i++) {
		    arr.push(createObj2(i & 1 ? i : undefined));
		}
		arr.splice(20, 60);
		var count = 0;
		for (var i = 0; i < 10; i++) {
		    if (arr[i].a !== undefined) {
		        count++;
		    }
		}
	});

	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("Object structure #jsbench #jsperf");
	console.log(new Array(30).join("-"));
	suite.run();
});
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8"/>
	<title>Object structure #jsbench #jsperf</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 () {
	function createObj1(x) {
	if (x === undefined) {
	var obj = {};
	obj.a = 1;
	return obj;
	}
	return {};
	}
	function createObj2(x) {
	return {
	a: x === undefined ? undefined : 1
	};
	}
	};


	suite.add("var arr = [];", function () {
	var arr = [];
	for (var i = 0; i < 100; i++) {
	arr.push(createObj1(i & 1 ? i : undefined));
	}
	arr.splice(20, 60);
	var count = 0;
	for (var i = 0; i < 40; i++) {
	if (arr[i].a !== undefined) {
	count++;
	}
	}
	});

	suite.add("var arr = [];", function () {
	var arr = [];
	for (var i = 0; i < 100; i++) {
	arr.push(createObj2(i & 1 ? i : undefined));
	}
	arr.splice(20, 60);
	var count = 0;
	for (var i = 0; i < 10; i++) {
	if (arr[i].a !== undefined) {
	count++;
	}
	}
	});

	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("Object structure #jsbench #jsperf");
	console.log(new Array(30).join("-"));
	suite.run();
	});