dependency of react-helmet uses legacy componentWillMount lifecycle method

[jfrolich]

The dependency react-side-effect uses componentWillMount, so react-helmet will not work in concurrentMode.

[jfrolich]

gaearon/react-side-effect#54

[danielweck]

Looks like react-helmet-async is a useful alternative:
https://github.com/staylor/react-helmet-async

[goldmont]

Looks like react-side-effect v2.0.0 now uses UNSAFE_componentWillMount.

Thus, no more warnings in the console.

[eduard-malakhov]

I confirm, after manually upgrading react-side-effect to v2.0.0, the warning is gone.

[kevr]

Looks like react-helmet-async is a useful alternative:
https://github.com/staylor/react-helmet-async

No, it's not. Creating another package just to undeprecate something so trivial is not an alternative, it's a cop out.

[samuraime]

before react-helmet update its dependency, a temporary workaround in package.json

  "resolutions": {
    "react-side-effect": "^2.1.0"
  }

[cwelch5]

Thanks for everyone's patience. We are actively working on 6.0.0 release. 6.0.0-beta.2 is available and will work with the latest React version.