TypeScript enhancement

[himself65]

Currently, yjs do have some typescript decorations for basic usage, but it needs to be stronger and more understood by people in typescript.

For example,

export class YMap<MapType> extends AbstractType<YMapEvent<MapType>> implements Iterable<MapType> {
// ...
}

In this type, MapType is the value allowed by this map. But there are no key restrictions for this type. So in the downstream code, I have to write many as for typecasting.

Also, there are no restrictions on both in yDoc.

const yMap = doc.getMap('x') // not a good type
const yMap2 = doc.getMap('x') as Y.Map<string | number>
yMap.get('1') // this is string or number

The expected types

This is an example from my repository that enhances the map type.

import type { Map as YMap } from 'yjs'

export interface ExtendsYMap<Data extends Record<string, unknown>, Keys extends keyof Data & string = keyof Data & string> extends YMap<any> {
  clone (): ExtendsYMap<Data, Keys>

  delete (key: Keys & string): void

  set<Key extends Keys> (key: Key, value: Data[Key]): Data[Key]

  get<Key extends Keys> (key: Key): Data[Key]

  has<Key extends Keys> (key: Key): boolean

  clear (): void
}

[himself65]

Related: https://discuss.yjs.dev/t/extending-yjs-types-without-breaking-everything/769

[strangecamelcaselogin]

While this is a more general issue, I think it is related to #352