fix typescript types after type optimization and cast, add castToSnapshot and castToReferenceSnapshot

[xaviergonz]

Basically since the fix to make types faster apparently some stuff got broken. This PR fixes:

• Creation type being downgraded to any in some circumstances
• cast being broken and basically becoming a fancy "as any"

Additionally:

• lots of type fixes to by moving IStateTree to the T part of the type rather than to create/model instance type
• added castToSnapshot to cast models used inside a create method.
• added castToReferenceSnapshot to cast models to their reference type (string | null) inside a create method
• cast once more now doesn't compile if used outside an assignment operation
• reference types snapshots are properly typed as string|number (therefore the new castToReferenceSnapshot)
• arrays mutate operations (push, splice, etc) now support creation/snapshot types without the need to cast them
• IComplexType has been removed since now it is equivalent to IType<any, any, ... & IStateTreeNode>

[xaviergonz]

@mweststrate thoughts about the addition of castToSnapshot?

[Bnaya]

Maybe we could advice the users to use getSnapshot instead?

[xaviergonz]

well, that's what mst does internally, but one of its key features is that it also supports constructs such as this

function f(childModel: SnapshotOrInstance<typeof ChildModel>) {
  self.rootModel = RootModel.create({
    child: castToSnapshot(childModel)
  });
}

to do that otherwise you'd have to either force cast it to as any as SnapshotIn<typeof ChildModel> (which won't tell you if something is wrong)

or with getSnapshot something like

function f(childModel: SnapshotOrInstance<typeof ChildModel>) {
  self.rootModel = RootModel.create({
    child: isNode(childModel) ? getSnapshot(childModel) : childModel
  });
}

which would be unneeded code (and I think won't compile, not 100% sure)

[xaviergonz]

Just made sure the .d.ts files generated don't get bigger (spoiler: they don't, they are exactly the same)

[xaviergonz]

@mweststrate pr done

[mweststrate]

@xaviergonz changes look good to me! (Granted, my review was quite superficial, as you are now way deeper into the subtleties of the TS type system then I am :)).

One question, did you check whether this negatively impacts the compilation / autocompletion speed, just to not undo the benefits of the previous PR?

Thanks!

[xaviergonz]

Yep I did! Quoting myself

Just made sure the .d.ts files generated don't get bigger (spoiler: they don't, they are exactly the same)

[mweststrate]

Doh! Approved then :) Op ma 19 nov. 2018 om 16:56 schreef Javier Gonzalez < notifications@github.com>:

…

Yep I did! Quoting myself Just made sure the .d.ts files generated don't get bigger (spoiler: they don't, they are exactly the same) — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#1074 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABvGhP8MUTqKDGwvOA-UjUZRTfh77rC-ks5uwtSYgaJpZM4YTqBq> .