Validate array argument for promise-array related functions

[jsor]

Reject all() / race() / any() / some() / map() / reduce() when called with a non-array.

all(null)
    ->otherwise(function(\InvalidArgumentException $e) {
        assertEquals('Expecting an array or a promise which resolves to an array, got NULL instead.' , $exception->getMessage());
    });

[clue]

👍 for rejecting invalid input

But then again what is valid input here? :-)

[jsor]

At the moment, it is an array or a promise which resolves to an array. Passing anything other produces

all(null)
    ->then(function($value) {
        assertEquals([], $value);
    });

which i think is not an expected behaviour.

[clue]

which i think is not an expected behaviour

Yeah, I agree that we should handle this is in a more sane way 👍

However, now that we're already considering what is valid input, I would suggest using a stricter definition. For example, ES6-style promises limit the parameter to be an array of promises (or values which are considered like resolved promises): https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Global_Objects/Promise/all (which IMHO makes sense to me).

As such, does it make sense to pass a single Promise which resolves to an array of values? Do we have a valid use case for this?

[jsor]

As such, does it make sense to pass a single Promise which resolves to an array of values? Do we have a valid use case for this?

I've never used a single input promise.

Options:

• No change, allow input promise which resolves to an array, requires rejection with InvalidArgumentException for non-array input
• Typehint against array, does not require rejection for non-array input
• Allow array and \Traversable input, no typehint possible, requires rejection with InvalidArgumentException for non-array input

I'm unsure on this atm.

[clue]

No change, allow input promise which resolves to an array, requires rejection with InvalidArgumentException for non-array input

👎 on this unless we find a valid use case

• Typehint against array, does not require rejection for non-array input
• Allow array and \Traversable input, no typehint possible, requires rejection with InvalidArgumentException for non-array input

IMO both sound sane…

Some (random) thoughts:

• On success, the all() method resolves with an array, so for consistency it may make sense to require an input array
• Traversable and Iterator have valid use cases, though I'm failing to see how these would be beneficial here. Also, converting via iterator_to_array() is trivial.
• Permitting several input types means we have to use additional runtime checks which add to complexity. Also, this makes it harder to use type guessing (IDEs).
• Typehinting against array is trivial and requires no boilerplate. It probably fulfills 80%+ of the use cases anyway and converting to an array is trivial.

As such, I'm leaning towards using an array typehint 👍

[jsor]

As such, I'm leaning towards using an array typehint

👍