Promise helpers should throw a TypeError, if they receive the wrong data structure

[buschtoens]

It is so insidiously easy to forget [] when using all(). 😈

I've just spent 20 minutes debugging this piece of code:

yield all(
  this.verifyAddress(),
  this.verifyAge()
);

Can we please add proper type checks for these helper methods? I'm up for a PR!

[maxfierke]

Hi @buschtoens 👋 ! I'm going through the issue queue and hoping to close out any PRs that are stale. I know this is almost 2 years old, but are you still up for a PR on this one?