Add checks and enhance getTokenFromHeader function definition

[Anass-Daoudi]

Hi,

In this PR, I mainly add more checks to the function getTokenFromHeader and enhance its definition structure.

Thanks for the review!
Happy to get feedbacks :)

[Anass-Daoudi]

Hi @kentcdodds @anishkny,
Could you please do some little review to my PR :).
Thanks

[kentcdodds]

Seems fine to me, though I don't personally feel like these changes make the code easier to follow...

[Anass-Daoudi]

Thanks @kentcdodds for giving a look.
But I think, the code I propose is more safe. Isn't it?

[kentcdodds]

Technically yes, but I doubt that there's a situation where req.headers wouldn't be an object in this code path...

[Anass-Daoudi]

As I see, as this code is not statically typed, we can't confirm that this function will always receive req.headers as an object; as an example, an express middleware that sets by accident req.headers=to-some-primitive-value.

Or may be this sort of controls must be done in unit tests?

Correct me please.
Thanks @kentcdodds :)

[kentcdodds]

I personally don't feel like the risk is worth the extra effort. But I don't have any stake in this project, so do what you want.

[Anass-Daoudi]

Thanks @kentcdodds for being that reactive :)