Can you bind 'this' in an arrow function?

Question

You cannot rebind this in an arrow function. It will always be defined as the context in which it was defined. If you require this to be meaningful you should use a normal function.

From the ECMAScript 2015 Spec:

Any reference to arguments, super, this, or new.target within an ArrowFunction must resolve to a binding in a lexically enclosing environment. Typically this will be the Function Environment of an immediately enclosing function.

To be complete, you can re-bind arrow functions, you just can't change the meaning of this.

bind still has value for function arguments:

((a, b, c) => {
  console.info(a, b, c) // 1, 2, 3
}).bind(undefined, 1, 2, 3)()

Try it here: http://jsbin.com/motihanopi/edit?js,console

From the MDN:

An arrow function expression has a shorter syntax compared to function expressions and lexically binds the this value (does not bind its own this, arguments, super, or new.target). Arrow functions are always anonymous.

This means you cannot bind a value to this like you want.

You cannot use bind to change the value of this inside an arrow function. However, you can create a new regular function that does the same thing as the old arrow function and then use call or bind to re-bind this as usual.

We use an eval call here to recreate the arrow function you pass in as a normal function and then use call to invoke it with a different this:

var obj = {value: 10};
function arrowBind(context, fn) {
  let arrowFn;
  (function() {
    arrowFn = eval(fn.toString());
    arrowFn();
  }).call(context);
}
arrowBind(obj, () => {console.log(this)});

For years, js developers struggled with context binding, asked why this changed in javascript, so much confusion over the years due to context binding and the difference between the meaning of this in javascript and this in most of the other OOP languages.

All this leads me to ask, why, why! why would you wan't to rebind an arrow function! Those where created specially to solve all this issues and confusions and avoid having to use bind or call or whatever other way to preserve the scope of the function.

TL;DR

No, you cannot rebind arrow functions.

Do ES6 Arrow Functions Really Solve “this” In JavaScript

The above link explains that arrow functions this doesn't change with bind, call, apply functions.

It is explained with a very nice example.

run this in node v4 to see the "expected" behavior,

this.test = "attached to the module";
var foo = { test: "attached to an object" };
foo.method = function(name, cb){ 
    // bind the value of "this" on the method 
    // to try and force it to be what you want 
    this[name] = cb.bind(this); };
foo.method("bar", () => { console.log(this.test); });
foo.bar();