Inject variable into callback function scope

Question

Is this possible to add variable to callback scope? What I want to achieve is:

...
Foo.prototype.bar = function(fn) {
    var baz = "baz!";
    fn.call(this);
}
...

Foo.bar(function() {
    console.log(baz) // gives "baz!"
});

I know I can pass baz variable as an argument or this but I'm interested in something like above.

Answer 1

No, it's not possible. The only ways are the ones you pointed out: as an argument or in this.