Object.gave, an improvement on hasOwnProperty() checks in for..in loops

object_gave.js

var HOP = Object.prototype.hasOwnProperty.call.bind(Object.prototype.hasOwnProperty);

//Checks the prototype chain to see if the "giver" "gave" the "key" to the "obj".
Object.gave = function(giver,key,obj) {
    //If there are 2 arguments instead of 3, use the Function.prototype method.
    if (arguments.length === 2) {
        Function.prototype.gave.apply(this,arguments);
    }

    var last_prototype;
    while ( obj !== giver ) {
        if (HOP(obj,key) || (obj === last_prototype)) return false;
        last_prototype = obj;
        obj = Object.getPrototypeOf(obj);
    }

    return true;
};

//Like the above, but makes the Function prototype the "giver".
//This improves on hasOwnProperty() checks in for..in loops by allowing
//prototypal inheritance while still weeding out constructor prototypes.
//e.g.: for (key in obj) { if (!Object.gave(key,obj)) { ... } }
Function.prototype.gave = function(key,obj) {
    return Object.gave( this.prototype, key, obj );
};