javascript map vs imperative testing

testmap.js

<script>

//All tests run repeatedly until numbers stabilize (jit warmup)

//Node 7.7.4 NODE_ENV = production  - 42ms 
//Firefox 52.0.1 32bit 250 to 280ms
//Firefox 52.0.1 64bit 210 to 250 ms
//Chrome 57.0.2987.110 (64-bit)  45ms
function testImperative(values)
{
    var result = new Array(values.length);
    for (var i = 0; i < values.length;i++){
	    var x = values[i];
        result[i] = x*x;
    }
	return result
}

//Node 7.7.4 NODE_ENV = production - 986msms after JIT WARMUP
// Firefox 52.0.1 32bit 250 to 280 ms
// Firefox 52.0.1 64bit 210 to 250 ms
//Chrome 57.0.2987.110 (64-bit)  2000ms
function testMap(values) {
	return values.map(x => x*x);
}

//If you drop this down to 1 million Firefox
//performs comparably to node/chrome
//and map and imperative still tie
var testArray = new Array(10000000);

for (var i = 0; i < testArray.length;i++)
{
    testArray[i] = i;
}



for (var i = 0; i < 10; i++)
{
    var startTime = new Date().getTime();
    var x = testImperative(testArray);
    var endTime = new Date().getTime();
    console.log(endTime-startTime);
    console.log('map');
}

</script>