Literal object and function constructor

I took this test on http://jsperf.com/literal-obj-vs-function-obj and Literal wins on FF6, Opera 10, IE8, but the Function method faster on Chrome 13.0.782.112, so which one is a better method to use?

var A = {
    aa : function(){
        var i, j=[];
        var arr = ['Literal', 'Function'];
        for (i = 0; i < arr.length; i++){
            j[i] = arr[i];
        }
       return j[0];
    }
};
var A1 = A;
var A2 = A1;
A1.foo = ' Test';
alert(A1.aa() + A2.foo);

//Function test
function B(){
    this.bb = function(){
        var i, j=[];
        var arr = ['Literal', 'Function'];
        for (i = 0; i < arr.length; i++){
            j[i] = arr[i];
        }
        return j[1];
    }
}
var B1 = new B();
var B2 = new B();
B.prototype.foo = ' Test';
alert(B1.bb() + B2.foo);
开发者_如何转开发

To tell you the truth, the best that I have found is a mix:

function C() {
    var i, j = [],
        foo;

    return {
        bb: function() {

            var arr = ['Literal', 'Function'];
            for (i = 0; i < arr.length; i++) {
                j[i] = arr[i];
            }
            return j[1];
        },
        setFoo: function(val) {
            foo = val;
        },
        getFoo: function() {
            return foo;
        }
    }
}
var C1 = C();
var C2 = C();
C2.setFoo(' Test');
console.log(C1.bb(), C2.getFoo());

Whichever one you prefer. Speed should never be a concern unless it becomes a real problem in your app. What you're doing looks like premature optimization to me, which is a waste of time. Wait until you need to optimize your code, then optimize the parts that need to be reworked. This is trivial.

Chrome uses an optimisation called hidden classes that allows it to do faster access to object members.

I would bet that this optimisation is enabled only when the object is constructed via new, and as a result an object constructed via new would have faster member access than an object not constructed via new.

well, chrome has around 17% of the market share according to wikipedia. So use literals.

I doubt you're going to do anything intensive enough for the difference to matter.

Function style constructors give you the option of private variables, which is nice.