Deprecate isValidClass

[sebmarkbage]

We should deprecate isValidClass. In 0.13, any function that returns an object with a render method will be a valid class.

We probably don't want to assume that there is a valid prototype because that doesn't allow the module pattern to be used:

function MyComponent(props) {
  return {
    render: function() {
      return <div />;
    }
  };
}

It's really difficult to validate these without invoking them. This is where a static type system shines. For a dynamic check, isValidClass would turn into: typeof fn === 'function' which doesn't need its own function.

Generally, you'll want to validate something extra about the class anyway. E.g. will it have a getDOMNode method on it? Does it render into a table cell?

[zpao]

So you know we put out an RC already, right? We really should have decided this before that happened. But sure, let's deprecate it. Want to put up that PR?

[sebmarkbage]

I didn't see it coming until I started working on it. We can also deprecate it in 0.13 but that'd change the semantics to just be === 'function'.

I'll put up a PR and we can decide later.

[lijunle]

Hi, sorry for comment on an old post.

I have a question on your assertion. You mentioned that:

any function that returns an object with a render method will be a valid class.

But, the function created by React.createClass will not return an object containing a render method. Actually, it is:

{ type: { [Function] displayName: 'Test' },
  key: null,
  ref: null,
  _owner: null,
  _context: {},
  _store: { validated: false, props: {} } }

So, basically, the current existing React Classes does not meet your criteria. :(

Any idea on this?

---

PS. Using React.createElement(class) does not return an object containing render function, too.