Do safe state instead of setState #338

[WhatAKitty]

If you use this.setState in local component you should set @safestate and always use this.props.setStateSafe instead of native method this.setState, it will avoid Can only update a mounted or mounting component warning that caused by setting state while component has already been unmounted.

[afc163]

Can only update a mounted or mounting component

We should clear all async setState calls in componentWillUnmount instead of make a safe setState.

[afc163]

Don't use dispatch().then(), move the logic into sagas.

@ddcat1115 @nikogu

[WhatAKitty]

@afc163 that warning is not related to setState in componentWillUnmount.
If you use local component and do this.setState, this warning would show sometimes. Such as change page quickly. The main reason is that the component is being unmount and the react is trying to setState at sametime

[afc163]

https://reactjs.org/blog/2015/12/16/ismounted-antipattern.html

[WhatAKitty]

@afc163 yeah, if you place all of your data in redux, make safe state is actually unnecessary.
Like @gaearon said in facebook/react#2787 (comment)

But how about React state(local component state) ?

[afc163]

Same as global state, check the React post above.

The real problem is that we can't cancel dispatch().then() in componentWillUnmount due to the limitation of dva's API.

cc @sorrycc

[WhatAKitty]

@afc163 gitter？

[gaearon]

It’s not a great way of doing it IMO.

When you have a cancelable API, use it. If the API is not cancelable, you can create a cancelable wrapper for it, and use that wrapper.

In either case, patching this on the component level ignores the real problem: APIs that don’t let you cancel.

[WhatAKitty]

@gaearon Thanks for your suggestions.