Partial Application
You can do partial application:
// This lets us call the slice method as a function
// on an array-like object.
var slice = Function.prototype.call.bind(Array.prototype.slice);
function partial(f/*, ...args */) {
if (typeof f != 'function')
throw new TypeError('Function expected');
var args = slice(arguments, 1);
return function(/* ...moreArgs */) {
return f.apply(this, args.concat(slice(arguments)));
};
}
What Object is this Function Bound To?
Additionally, there’s a pretty straight-forward solution to the first part of your question. Not sure if this is an option for you, but you can pretty easily monkey-patch things in JS. Monkey-patching bind
is totally possible.
var _bind = Function.prototype.apply.bind(Function.prototype.bind);
Object.defineProperty(Function.prototype, 'bind', {
value: function(obj) {
var boundFunction = _bind(this, arguments);
boundFunction.boundObject = obj;
return boundFunction;
}
});
Just run that before any other scripts get run, and any script which uses bind
, it will automatically add a boundObject
property to the function:
function f() { }
var o = { };
var g = f.bind(o);
g.boundObject === o; // true
(Note: I’m assuming you’re in an ES5 environment above due to the fact that you’re using bind
.)