Eloquent deep comparison

JavaScript

function deepEqual(a, b) {
 	if (a === b) return true;
    
    if (a == null || typeof a != "object" || 
        b == null || typeof b != "object")
        return false;
    
    var propsInA = 0, propsInB = 0;
    
    for (var prop in a)
        propsInA += 1;
    
    for (var prop in b) {
        propsInB += 1;
        if (!(prop in a) || !deepEqual(a[prop], b[prop]))
            return false;
	}
    
    return propsInA == propsInB;
}

var obj = {here: {is: "an"}, object: 2};
console.log(deepEqual(obj, obj));
console.log(deepEqual(obj, {here: 1, object: 2}));
console.log(deepEqual(obj, {here: {is: "an"}, object: 2}));