Question

Can someone explain this function?

var bindbind = Function.prototype.bind.bind(Function.prototype.bind);

I understand the result it produce:

var bindedContextFunc = bindbind(function)(context);
bindedContextFunc(args);

But do not understand process of creating this functions, I mean part bind(Function.prototype.bind)

Answer 1

OK. We have three times the Function.prototype.bind function here, whose (simplified) code

function bind(context) {
    var fn = this;
    return function() {
        return fn.apply(context, arguments);
    }
}

I will abbreviate in a more functional style with lots of partial application: bind_fn(context) -> fn_context.

So what does it do? You have got bind.call(bind, bind) or bind_bind(bind). Let’s expand this to bind_bind. What if we now supplied some arguments to it?

bind_bind(bind) (fn) (context)

bind_bind(fn) (context)

bind_fn(context)

fn_context

Here we are. We can assign this to some variables to make the result clearer:

bindbind = bind_bind(bind)

bindfn = bindbind_anything(fn) // bind_fn

contextbindfn = bindfn_anything(context) // fn_context

result = contextbindfn_anything(args) // fn_context(args)