React 16 warning

[tizmagik]

Figure out why React 16 shows this warning:

Warning: Expected server HTML to contain a matching <title> in <div>.

You can see this in action with the example app:

npm run build
cd example
npm install
npm start

Then navigate to http://localhost:3000

[coymeetsworld]

I'll take a look

[adamgruber]

A quick look shows this might be an issue with using portals to render content outside of the root element. When React hydrates the DOM, it looks for a matching element in the server HTML but in this case can't find a <title> tag inside the root element so it throws a warning. Not sure this is fixable since this is the behavior you are going for.

[tizmagik]

Heh yea, this might be a use of React Portals in a way it wasn't intended to be used. But the use case feels legit! I'm hoping it's just a false negative warning or something.

Will try and get @gaearon 's attention sometime to see if this is legit or a hacky use of Portals that he recommends against. 😁

[gaearon]

File an issue in React with an isolated small example please.

[tizmagik]

Filed facebook/react#11169