React 17 support

[Thibaut-Fatus]

Version

• [email protected]
• [email protected]
• [email protected]
• [email protected]

Test Case

https://codesandbox.io/s/react-router-forked-zeizl?file=/index.js
which does actually work, but the exact same example does not locally

Steps to reproduce

• yarn install these packages
• try to use any hooks from react-router-dom (for instance useParams)

you'll get an error Invalid hook call

because [email protected] is resolved and installed in node_modules/react-router-dom/node_modules instead of using the root [email protected]

• deleting the directory node_modules/react-router-dom/node_modules/react

or

• adding an alias key in react-script webpack.config like so react: path.resolve('node_modules/react'),

solves the issue

Expected Behavior

react-router-dom has

  "peerDependencies": {
    "react": ">=15"
  },

which should allow [email protected] resolution ?

Actual Behavior

We should be able to use react-router-dom hook useParams without having invalid hook call with react 17

[Thibaut-Fatus]

requesting [email protected] in the host package.json fixes the issue since react-router does not install a duplicate version then, but it would be nice to be able to use react 17

[timdorr]

Yeah, there's nothing preventing you from installing React 17 and using that. I've got it in place in our production app right now and it works A-OK.

Something is wrong with your installation tooling if it's resolving a different version of React. Router shouldn't have it's own React module under any version of React, as many of the internal instances React uses are going to mismatch and cause issues.

[mateja176]

Yeah, there's nothing preventing you from installing React 17 and using that. I've got it in place in our production app right now and it works A-OK.

Something is wrong with your installation tooling if it's resolving a different version of React. Router shouldn't have it's own React module under any version of React, as many of the internal instances React uses are going to mismatch and cause issues.

I've encountered the same problem while using yarn and it may very well be an issue with yarn since react-router specifies

  "peerDependencies": {
    "react": ">=15"
  },

Which does not exclude v17.

[alippai]

It works, but duplicate "react-is" module versions are loaded and bundled, both v16 and v17 (correctly as this is what the react-router specifies in it's package.json). I don't see how the current package.json would allow react v17 (this is true for both v5 and v6)

[bezsinnyidmytro]

does it have any solution to leave host app with react v17 and not have 2 versions of react in the bundle?
I still see that both 16 and 17 is added to package-lock