react: Allow changing instance in uppy prop

[goto-bus-stop]

When changing the Uppy instance, the components will uninstall the UI plugin from the old instance, and install it to the new instance.

One other thing that I wanted to do is warn when you create the Uppy instance in the render() method. that becomes harder when this use case is supported. If we didn't support changing instances, we could simply throw an error if the uppy prop ever changes. If we support changing instances, I'm not sure how we'd detect Uppy instances being created in render().

[arturi]

👍

Should we make a note in the docs, in bold, that uppy shouldn’t be initialized in render? Issues about this arise quite often: #1243.

[goto-bus-stop]

Maybe we can also provide a Component to do something like

<UppyProvider
  initialize={uppy => {
    uppy.use(Transloadit, {})
  }}
  render={uppy => (
    <MyComponent uppy={uppy} />
  )}
/>

to manage the lifecycle of an Uppy instance.

Or a withUppy HOC like

const enhance = withUppy(uppy => {
  uppy.use(Transloadit, {})
})
const MyComponent = ({ uppy }) => (
  <Dashboard uppy={uppy} />
)
const MyComponentWithUppy = enhance(MyComponent)

Or we could wait for React Hooks to be out of alpha, because I think it'll support the exact lifecycle that we need.

[oyeanuj]

@goto-bus-stop +1 for react-hooks support here!