react-navi causing error in StrictMode

SideEffect is causing an error in StrictMode.

SideEffect.prototype.componentWillMount = function componentWillMount() {
  mountedInstances.push(this);
  emitChange();
};

found this in react-navi/dist/umd/react-navi.js. Using StrictMode it causes this error:

Warning: Unsafe lifecycle methods were found within a strict-mode tree:
    in StrictMode (at App.tsx:7)
    in App (at src/index.tsx:6)

componentWillMount: Please update the following components to use componentDidMount instead: SideEffect(NullComponent)

Learn more about this warning here:
https://fb.me/react-strict-mode-warnings

[jamesknelson]

I think I’m leaning that way too, although you’re right that it’d be a breaking change.

The next release should provide a way to add custom matchers like withHead and withTitle, so perhaps what I’ll do is extract withHead/withTitle to a separate package in the next release, and switch that package to use react-helmet-async at the same time.

In the meantime, if react-helmet-async is API compatible with react-helmet, I would accept a PR to switch over in a minor release to help with <StrictMode>.

[jamesknelson]

This looks to be caused by the dependency on react-helmet. I’m going to need to update Navi to either use react-helmet-async, or just remove react-helmet and leave head/title management to the application.

Would love to hear any thoughts on the best option here.