JavaScript: unexpected typeof result

Question

I have an array iterator function:

function applyCall(arr, fn) {
  fn.call(arr[0], 0, arr[0]);
}

and some code

var arr1 = ['blah'];
applyCall(arr1, function (i, val) {
  alert(typeof this); // object    WHY??
  alert(typeof val); // string
  alert(typeof(this === val)) // alerts false, expecting true
});

Why is typeof this within the inline function object instead of string?

jsfiddle here

Answer 1

When a method is called in JavaScript, it internally sets this to the calling object: https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Function/apply

...and primitive values will be boxed.

By "boxed," they mean that the primitive is wrapped in an Object. Note that this only applies to the first argument to apply/call. The other arguments become function parameters that are not "boxed."