Added 'objectOf' PropType validator to iterate on objects and validate properties.

[mathieumg]

The rationale behind this is when you have object literals used as dictionaries and you want to validate each property (without knowing its name ahead of time). PropTypes.shape allows to validate specific properties, but this rather iterates on the properties of an object (no matter their name) and validates their content (which then can be any of the PropTypes). It works very similarly to arrayOf, so I strongly inspired myself from its code both for the implementation and the tests.

If you're interested in merging this, I imagine the name can change but I had trouble coming up with something as straightforward and unambiguous.

[syranide]

@spicyj @zpao I think we settled on using hasOwnProperty() in the rest of the React code base right?

[mathieumg]

Basically you want me to wrap it with if (propValue.hasOwnProperty(key)) for each iteration?

[syranide]

Yep. The issue #1385 I was thinking of is still open it seems, but I believe we're mostly using hasOwnProperty elsewhere, I personally don't really mind either. Can wait for @zpao @spicyj or whoever to weigh in if you want.

[mathieumg]

I don't mind adding it to be on the "safe side", especially if it's already the approach. Prop validation is dev-only anyway so that's negligible overhead.

[syranide]

It seems like a sound idea and the code looks great to me.
👍 Good job!

[zpao]

Interestingly enough, we just had somebody work on almost exactly this on Friday internally (hi @dschafer!). I wasn't sure if we really wanted to support it in core since it's a bit specialized, but perhaps I was wrong...

[sophiebits]

We also wanted this at KA two weeks ago.

For naming, I was thinking perhaps map or dict. Using map is nice in that it matches the ES6 Map, but perhaps also confusing for the same reason.

[chenglou]

👍
One day ReactPropTypes will reach feature-parity with Haskell's type system (jk).

[zpao]

The version we had internally used the name dictOf but I actually think objectOf is the best fit. It follows arrayOf and says object which matches the type we already have.

I don't have any code comments, so I'm going to go ahead and pull this in.

[zpao]

Nit: please remove trailing whitespace here

[sebmarkbage]

IMO, using objects as dictionaries should be highly discouraged. You should be using an ES6 Map and we could add an mapOf function.

[vjeux]

@sebmarkbage no one is going to be able to use ES6 Map in a long time. I think that it's worth supporting objectOf in the meantime.

[sebmarkbage]

@vjeux We'll require a shim of ES6 Map in React core soon anyway. So everyone will be able to use it.

[chenglou]

Internally merged. We can have both!