kadamwhite/index.html

## index.html
<!doctype html>
<html>
<head>
<meta charset="utf-8"/>
</head>
<body>
<script>
var seeded = false;
var lcg = (function() {
var m = 4294967296,a = 1664525,c = 1013904223,seed, z;
return {setSeed:function(val) {z = seed = (val == null ? Math.random() * m : val) >>> 0;},
getSeed:function() {return seed;},rand:function() {z = (a * z + c) % m;return z / m;}};}());

// Current implementation
function random(min, max) {
  var rand;
  if (seeded) {
    rand  = lcg.rand();
  } else {
    rand = Math.random();
  }
  if (arguments.length === 0) {
    return rand;
  } else
  if (arguments.length === 1) {
    if (arguments[0] instanceof Array) {
      return arguments[0][Math.floor(rand * arguments[0].length)];
    } else {
      return rand * min;
    }
  } else {
    if (min > max) {
      var tmp = min;
      min = max;
      max = tmp;
    }
    return rand * (max-min) + min;
  }
}

// Proposed implementation
function randomNoArgs(min, max) {
  var rand;
  if (seeded) {
    rand  = lcg.rand();
  } else {
    rand = Math.random();
  }
  if (typeof min === 'undefined') {
    return rand;
  } else
  if (typeof max === 'undefined') {
    if (min instanceof Array) {
      return min[Math.floor(rand * min.length)];
    } else {
      return rand * min;
    }
  } else {
    if (min > max) {
      var tmp = min;
      min = max;
      max = tmp;
    }
    return rand * (max-min) + min;
  }
}

// Test Harness

var obj = {
  random: random,
  randomNoArgs: randomNoArgs
};

function lookup( method ) {
  return function() {
    return obj[ method ]();
  }
}

var methodsToTest = [
  { method: random,                 name: 'basic' },
  { method: lookup('random'),       name: 'object lookup' },
  { method: random,                 name: 'bound function' },
  { method: randomNoArgs,           name: 'basic without "arguments"' },
  { method: lookup('randomNoArgs'), name: 'object lookup without "arguments"' },
  { method: randomNoArgs,           name: 'bound function without "arguments"' }
];

var results = methodsToTest.reduce(function( resultsArrs, testCfg ) {
  resultsArrs[ testCfg.name ] = [];
  return resultsArrs;
}, {});

// Test method
function test( method, name ) {
  var startTime = new Date();
  // Un-comment these if you want to see the results stream to console as they come in:
  // console.time( name );
  for (var i = 0; i < 1000000; i++) {
    method();
  }
  // console.timeEnd( name );
  results[ name ].push( endTime = new Date() - startTime );
}

// The length of this array determines how many passes will be made for each method
var arr = [];
for (var i = 0; i < 100; i++) { arr.push(null); }

// Reduce over the array and return a promise at each step so tests do not lock browser
var allTestsDone = methodsToTest.reduce(function(prom1, testCfg) {
  return prom1.then(function() {
    console.log( 'Starting tests for ' + testCfg.name );
    return arr.reduce(function(prom) {
      return prom.then(function() {
        return new Promise(function(resolve, reject) {
          setTimeout(function() {
            test( testCfg.method, testCfg.name );
            resolve();
          }, 1);
        });
      });
    }, Promise.resolve() )
  });
}, Promise.resolve());

allTestsDone
  .then(function() {
    Object.keys( results ).forEach(function( key ) {
      console.log( 'Average runtime for ' + key + ':' );
      console.log( (results[ key ].reduce(function( sum, val ) {
        return sum + val;
      }, 0 ) / results[key].length).toFixed(2) + 'ms' )
    });
  })
  .catch(function(err) { console.error( err ); });

</script>
</body>
</html>
	<!doctype html>
	<html>
	<head>
	<meta charset="utf-8"/>
	</head>
	<body>
	<script>
	var seeded = false;
	var lcg = (function() {
	var m = 4294967296,a = 1664525,c = 1013904223,seed, z;
	return {setSeed:function(val) {z = seed = (val == null ? Math.random() * m : val) >>> 0;},
	getSeed:function() {return seed;},rand:function() {z = (a * z + c) % m;return z / m;}};}());

	// Current implementation
	function random(min, max) {
	var rand;
	if (seeded) {
	rand = lcg.rand();
	} else {
	rand = Math.random();
	}
	if (arguments.length === 0) {
	return rand;
	} else
	if (arguments.length === 1) {
	if (arguments[0] instanceof Array) {
	return arguments[0][Math.floor(rand * arguments[0].length)];
	} else {
	return rand * min;
	}
	} else {
	if (min > max) {
	var tmp = min;
	min = max;
	max = tmp;
	}
	return rand * (max-min) + min;
	}
	}

	// Proposed implementation
	function randomNoArgs(min, max) {
	var rand;
	if (seeded) {
	rand = lcg.rand();
	} else {
	rand = Math.random();
	}
	if (typeof min === 'undefined') {
	return rand;
	} else
	if (typeof max === 'undefined') {
	if (min instanceof Array) {
	return min[Math.floor(rand * min.length)];
	} else {
	return rand * min;
	}
	} else {
	if (min > max) {
	var tmp = min;
	min = max;
	max = tmp;
	}
	return rand * (max-min) + min;
	}
	}

	// Test Harness

	var obj = {
	random: random,
	randomNoArgs: randomNoArgs
	};

	function lookup( method ) {
	return function() {
	return obj[ method ]();
	}
	}

	var methodsToTest = [
	{ method: random, name: 'basic' },
	{ method: lookup('random'), name: 'object lookup' },
	{ method: random, name: 'bound function' },
	{ method: randomNoArgs, name: 'basic without "arguments"' },
	{ method: lookup('randomNoArgs'), name: 'object lookup without "arguments"' },
	{ method: randomNoArgs, name: 'bound function without "arguments"' }
	];

	var results = methodsToTest.reduce(function( resultsArrs, testCfg ) {
	resultsArrs[ testCfg.name ] = [];
	return resultsArrs;
	}, {});

	// Test method
	function test( method, name ) {
	var startTime = new Date();
	// Un-comment these if you want to see the results stream to console as they come in:
	// console.time( name );
	for (var i = 0; i < 1000000; i++) {
	method();
	}
	// console.timeEnd( name );
	results[ name ].push( endTime = new Date() - startTime );
	}

	// The length of this array determines how many passes will be made for each method
	var arr = [];
	for (var i = 0; i < 100; i++) { arr.push(null); }

	// Reduce over the array and return a promise at each step so tests do not lock browser
	var allTestsDone = methodsToTest.reduce(function(prom1, testCfg) {
	return prom1.then(function() {
	console.log( 'Starting tests for ' + testCfg.name );
	return arr.reduce(function(prom) {
	return prom.then(function() {
	return new Promise(function(resolve, reject) {
	setTimeout(function() {
	test( testCfg.method, testCfg.name );
	resolve();
	}, 1);
	});
	});
	}, Promise.resolve() )
	});
	}, Promise.resolve());

	allTestsDone
	.then(function() {
	Object.keys( results ).forEach(function( key ) {
	console.log( 'Average runtime for ' + key + ':' );
	console.log( (results[ key ].reduce(function( sum, val ) {
	return sum + val;
	}, 0 ) / results[key].length).toFixed(2) + 'ms' )
	});
	})
	.catch(function(err) { console.error( err ); });

	</script>
	</body>
	</html>