[SelectField] Composeable Items.

[alitaheri]

I think all combo boxes especially the SelectField component should be composeable instead of requiring an object to generate their items from.
don't you think this is better:

<SelectField selectedValue={1 /* optional */} onChange={(value, payload) => {/*...*/}}>
  <SelectItem value={1} payload={{foo:1}}/>
  <SelectItem style={...} value={2} payload={{foo:'something'}}/>
  <SelectItem value={3} payload={{foo:2}}/>

  <SelectGroup title='Barz'>
    <SelectItem value={7} payload={{bar:1}}/>
  </SelectGroup>

  <SelectItem value={8} payload={{foo:5}}/>
</SelectField>

This will provide a huge flexibility (value can be anything comparable) and payload can be anything. Besides many other customizations will also be possible.
Thoughts? @oliviertassinari @shaurya947

[oliviertassinari]

I'm wondering if this couldn't be applied to the Autocomplete too.
I think that it's a good idea. My only concern would be regarding performances.
Could we still implement an efficient shouldComponentUpdate?
I'm wondering because the children of the SelectField will never be equals between two render, but an object property can.

[alitaheri]

I think if we use react-list we wouldn't need to worry about performance here. You can have at most 10 items in view.

[oliviertassinari]

Well, react-list accept a itemRenderer() property and a lenght property.
Their API seems close to what SelectField is now and far from what we want to move to.

I'm assuming that we can find a way to make them work together with this new SelectField API.
However handling an update will be tricky, react-list need an property to rely on to know if it has to rerender or not. What are we going to use?

[alitaheri]

Hmmmm, I guess this needs more thought and community feedback then.

[shaurya947]

@subjectix @oliviertassinari I definitely think that this would be a better way of using SelectField.

@subjectix can you elaborate more on SelectGroup vs SelectItem?

@oliviertassinari regarding performance, is it really that bad? If we implement a shouldComponentUpdate for the outer SelectField component that compares the value, style and payload prop of each child, is that any better than what react would do under the hood?

[alitaheri]

I definitely think that this would be a better way of using SelectField.

I'll try to work out the semantics for this.

can you elaborate more on SelectGroup vs SelectItem?

@shaurya947 That was just for show, wanted to express the capabilities it can provide. Something like categorization within the SelectField's Menu.

[oliviertassinari]

I really like this idea. I also noticed that with the new popover teleportation feature. It's really hard to test a SelectField.

[alitaheri]

@oliviertassinari Yeah >.> it is. that's why we have to do something about it all. I very much like the idea @newoga proposed in #2416.