Exploring ES2016 Decorators (opens in new tab)

"A decorator is just an expression that will be evaluated and has to return a function." It seems to me that it's just sugar for wrapping functions... is there some reason that couldn't be optimized?

It's specifically a proposal for 2016, and described as such in the very first sentence.

ES Next doesn't exist.

Unfortunately, due to hoisting decorating top-level functions is a real pain [1].

What should the behavior of:

    myMagicFunction();

    var myDecorator = require('myDecorator');

    @myDecorator
    function myMagicFunction() {
      // TODO: Make magic
    }

be?

- `myDecorator`'s require statement is hoisted above `myMagicFunction`'s declaration so that `myMagicFunction` is always decorated? (Results in a given `var`'s behavior changing depending on whether it is invoked as a decorator, an exceedingly non-obvious behavior)

- Function hoisting doesn't happen for decorated functions (non-obvious, possibly hard to implement).

- Function hoisting happens but the decorator is not hoisted (resulting in a sometimes-decorated function).

These problems don't admit of a simple solution (at least as far as I can see).

  [1]: https://github.com/wycats/javascript-decorators/issues/4