Convert methods to unselfish functions

unselfish.js

Function.prototype.unselfish = (function(Fp, Ap) {
    var applyMethod = Fp.apply,
        callMethod = Fp.call;

    var apply = callMethod.bind(applyMethod),
        call = callMethod.bind(callMethod);

    var sliceMethod = Ap.slice;

    return function unselfish() {
        var f = this;
        return function(self) {
            return apply(f, self, call(sliceMethod, arguments, 1));
        };
    };
})(Function.prototype, Array.prototype);

var hasOwn = Object.prototype.hasOwnProperty.unselfish();

console.log(hasOwn({}, "toString")); // false
console.log(hasOwn({foo:1}, "foo")); // true

I'm writing in a "paranoid style", where as long as the library is initialized before any untrusted code, it will continue to work properly no matter how much someone trashes the standard libraries. Notice how your version calls call.bind, which could break if someone modifies Function.prototype.bind or call.__proto__.

For most applications this probably doesn't matter, but I was just playing around with just how "high-integrity" an implementation you can write.

Dave

I get it, thanks for clarification, good tip.