How to handle componentWillReceiveProps deprecation

[Mo Kouli]

Type of issue

Question/Discussion

Description

componentWillReceiveProps is soon going to be deprecated in future versions of react.

The new recommendation for making side-effects when there is a difference between current + previous props is to do so in componentDidUpdate (see: https://reactjs.org/docs/react-component.html#componentdidupdate)

When react enables async rendering in future releases of react, this will break lifecycle methods into "render" phase and "commit" phase. Methods in the "render" phase (includes componentWillReceiveProps) are meant to be side-effect free as they might be called multiple times.

componentDidMount and componentDidUpdate are called in the "commit" phase and are the recommended place for side-effects (includes network calls). see: https://reactjs.org/docs/strict-mode.html#detecting-unexpected-side-effects

twitter thread with more context: https://twitter.com/ken_wheeler/status/983022255746768897?s=20

Current behavior

opts.componentWillReceiveProps = true causes sideEffect to be called each time we receive new props.

Expected behavior

I think at a bare minimum prepared should support a new opts.componentDidUpdate that behaves the same as componentWillReceiveProps. Adding this feature would be BC and allow people to switch to using that option for the same use case as opts.componentWillReceiveProps was supposed to address.

At some point this library needs to drop support for opts.componentWillReceiveProps as it is currently implemented, I see 2 options in this case:

1. Still support opts.componentWillReceiveProps option but have the underlying implementation call prepare in componentDidUpdate. ie in componentDidUpdate call sideEffect if opts.componentDidUpdate || opts.componentWillReceiveProps

This allows a new version to be published without needing a major version bump.

2. Completely drop support for opts.componentWillReceiveProps and bump major.