Not binding an anonymous function in Coffeescript executes with `this` bound to `window` ... but arrow functions do not provide a non-null `this`

 _.defer -> @someWindowProp?

I get this output:

_.defer => { ... }

Technically, this is not preserving behaviour since this is now null and this causes an exception to be thrown. In the Coffeescript runtime (i.e: using just function then you get a case where you would end up just being run in the window context. In most cases in our code base, it’s actually an error! (someone thought they were bound but were not and did a null check for other reasons) but I guess technically this goes against “out of the box correctness”

Not sure how to fix – I have a few ideas but not 100% there.

[hilts-vaughan]

Thanks for taking a look. That’s what I gathered as well. As I said, in my case most of these are actually in error and someone isn’t actually looking for a window prop, rather, a class prop but forgot to bind, so there was already a logic bug. In some ways, decaffeinate did me a favour. 😉

Thanks.

[hilts-vaughan]

oops, I may have simplied too much. I’ll try and create a REPL for you – sorry, I can’t link to proprietary code and may have “trimmed” out the source of the problem.

Lemme do that for you.