[Select] Support object value

[yezhi780625]

In Select component, the property value support object type. The value will pass into Input and InputBase components. But it is not supported in Input and InputBase .

What's more, I think that the propertydefaultValue should support the same types as property value.

Closes #10845

[eps1lon]

I will voice my concerns once again because this is increasingly magic since the value will be cast to string. People should do that explicitly so that the component appears to be less magic. Allowing numbers is already bad as it is since numbers will go in but strings will come out.

Especially for something like objects it doesn't make much sense to allow them since most of them will generate the same value ([object Object]).

[oliviertassinari]

I'm not a fan either, but many people ask for it. At this point, we might just use any for the propType, like React is doing for <input>. Now, most people use an XHR to send the form values to the server. They don't care about the [object Object] DOM casting. Also, as we don't cast objet to string in the non native select implementation, this works.

[eps1lon]

Well if you access event.target.value then you should care about casting. I was hoping we could add a more predictable wrapper around input since type coercion is imo one of the bigger issues in JS since it can't be addressed with linters.

But since we already allowed this with numbers we might as well be consistent. PropTypes.any it is.

[oliviertassinari]

Having object select support definitely comes with a cost :/. Does it worth it?

[oliviertassinari]

I'm going to merge this pull-request. To sum up:

• The native select implementation doesn't support object value. It's not possible, and that's for the best.
• The non-native select implementation (default) supports it but comes with a tradeoff. It can't be used for any standard client -> server form posting. The object value will be cast to "[object Object]" then rendered into the DOM as a string. The native input React elements don't raise any warning about it: https://codesandbox.io/s/o4w168k2lz. I have looked at react-select, they don't even have any propTypes. In some way, this change makes us less opinionated. I haven't added any documentation for this behavior, I would rather not encourage it and keep it "under the radar".