[Fiber] Check for requestAnimationFrame throws when react-dom is required on the server

[ide]

Do you want to request a feature or report a bug?
Bug-ish

What is the current behavior?
When doing server-side rendering with React, requiring react-dom (which transitively requires ReactDOMFrameScheduling.js) throws an exception because rAF is not defined.

Invariant Violation: React depends on requestAnimationFrame. Make sure that you load a polyfill in older browsers.
    at invariant (app/node_modules/fbjs/lib/invariant.js:44:15)
    at Object.<anonymous> (app/node_modules/react-dom/lib/ReactDOMFrameScheduling.js:30:3)

This can happen if you have a universal component that has top-level imports of client-side libraries, like react-router-scroll, that require react-dom instead of react-dom/server.

What is the expected behavior?
I would expect not to get this error unless requestAnimationFrame were actually called. Ex: lazily check for rAF and define rIC.

Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?
React 16.0.0-alpha.3 on Node 7.7.1. This started happening in alpha 3, which shipped and enabled Fiber.

[ide]

A workaround that achieves my expected behavior is for each consumer of React to define a little polyfill in a file that's imported before the others but I expect many people to run into this issue. This is what it looks like:

global.window = global;
window.addEventListener = () => {};
window.requestAnimationFrame = () => {
  throw new Error('requestAnimationFrame is not supported in Node');
};

[gaearon]

We could fix this by lazily initializing rAF polyfill, but now that I think of it, it seems unfortunate that merely importing findDOMNode (which is likely what components do) runs the whole client reconciler init code.

[ManasJayanth]

@gaearon Shouldn't it have been caught in the unit test

Also, more importantly, isn't requiring react-dom and running findDOMNode on server an anti-pattern, and that components must avoid them in hooks that run on the server?

[gaearon]

Also, more importantly, isn't requiring react-dom and running findDOMNode on server an anti-pattern, and that components must avoid them in hooks that run on the server?

You shouldn't run it on the server, but importing it is fine. Otherwise how would you write a component that uses findDOMNode on the client but still works on the server?

Shouldn't it have been caught in the unit test

No, the test doesn’t catch this because we set up a global rAF polyfill as part of our testing environment.

[ManasJayanth]

Edit: The PR is just for illustration. Just ran the unit tests. No linting and prettier run yet.

Opened a PR to put down the idea in code.

I moved the check for rAF inside the ReactFiberScheduler

But now, I lost the ability to throw if the rAF is not polyfilled. Is this the right place for the lazy check you mentioned?