Warning for: PropTypes.object.isRequired when prop is `null`

[TrySpace]

As PropTypes is about the 'type' of prop, null is an empty object, but still a type of object, practically.

But still it warns:

 Warning: Required prop `profile` was not specified in `Element`. Check the render method of `OtherElement`.

I don't think this is supposed to happen.

It stops warning after it is not null anymore. I'm pretty sure it should only warn when it is undefined ?

[syranide]

null is the equivalent of no value and is not an object (empty or otherwise). If you don't want it to warn for null then don't make it required, it has the same effect. Testing for the presence of a key is not something I would recommend.

[jimfb]

I agree. I can't think of very many use cases where you would want to force a user to specify a value, but would be willing to accept null as a valid value. For practical purposes, the isRequired warning for null is sensible and expected behavior.

[ptim]

related: #2166
(this issue still shows up prominently in search results)

[wardpenney]

A common use case I see is React rendering a component before an API call for data has finished. The first render would render, for example, a list of items (items: null). Then the API call finishes, and now items is populated with an array.

[Noitidart]

I am trying to do PropTypes.oneOfType([null, PropTypes.object]).isRequired, so either null or an object, is this not possible right now?

[GabrielDelepine]

According to the CHANGELOG, since 15.4.0 it's suppose to be possible

[misantronic]

Actually, it's the opposite in 15.4.0: Required PropTypes now fail with specific messages for null and undefined.

I am also facing this issue.
@Noitidart 's workaround is not working for me. It throws an error saying:
Failed prop type: The prop valueis marked as required inSelect, but its value is null.

I find it really useful to require a property but also allow null values.

[jharris4]

+1 for allowing null somehow.

We have a use case where our configuration is loaded via JSON, and there are several label configuration options that specify a string that should be displayed, something like this:

{
  "title": "my title"
}

So when no title should be displayed, we use null to denote that case:

{
  "title": null
}

(Adding parallel hasTitle: false would be prohibitive as we have dozens of these settings.)

For JSON content, using null is a very useful way to distinguish between not defined (undefined) versus deliberately omitted (null).

[jquense]

you can allow null, set the propType to not be required, since it's not required :P

[hzhu]

@jquense thanks that's super helpful! I had deleted my previous comment because this SO answer said the same thing.