mobx-keystone/src/snapshot/SnapshotOf.ts

A MobX powered state management solution based on data trees with first class support for TypeScript, snapshots, patches and much more

import type { Frozen, frozenKey } from "../frozen/Frozen"
import type { AnyModel } from "../model/BaseModel"
import type { modelIdKey, modelTypeKey } from "../model/metadata"
import type { ModelFromSnapshot, ModelToSnapshot } from "../modelShared/BaseModelShared"
import type { ArraySet, ObjectMap } from "../wrappers"

// snapshot out

// infer is there just to cache type generation

export type SnapshotOutOfObject<T> = {
  [k in keyof T]: SnapshotOutOf<T[k]> extends infer R ? R : never
}

export type SnapshotOutOfModel<M extends AnyModel> = ModelToSnapshot<M>

export interface SnapshotOutOfFrozen<F extends Frozen<any>> {
  [frozenKey]: true
  data: F["data"]
}

export interface SnapshotOutOfObjectMap<V> {
  items: { [k: string]: SnapshotOutOf<V> }
  [modelTypeKey]?: string
  [modelIdKey]: string
}

export interface SnapshotOutOfArraySet<V> {
  items: SnapshotOutOf<V>[]
  [modelTypeKey]?: string
  [modelIdKey]: string
}

export type SnapshotOutOf<T> =
  T extends ObjectMap<infer V>
    ? SnapshotOutOfObjectMap<V> extends infer R
      ? R
      : never
    : T extends ArraySet<infer V>
      ? SnapshotOutOfArraySet<V> extends infer R
        ? R
        : never
      : T extends AnyModel
        ? SnapshotOutOfModel<T> extends infer R
          ? R
          : never
        : T extends Frozen<any>
          ? SnapshotOutOfFrozen<T> extends infer R
            ? R
            : never
          : T extends object
            ? SnapshotOutOfObject<T> extends infer R
              ? R
              : never
            : T

// snapshot in

export type SnapshotInOfObject<T> = {
  [k in keyof T]: SnapshotInOf<T[k]> extends infer R ? R : never
}

export type SnapshotInOfModel<M extends AnyModel> = ModelFromSnapshot<M>

export interface SnapshotInOfFrozen<F extends Frozen<any>> {
  [frozenKey]: true
  data: F["data"]
}

export interface SnapshotInOfObjectMap<V> {
  items?: { [k: string]: SnapshotOutOf<V> }
  [modelTypeKey]?: string
  [modelIdKey]: string
}

export interface SnapshotInOfArraySet<V> {
  items?: SnapshotOutOf<V>[]
  [modelTypeKey]?: string
  [modelIdKey]: string
}

export type SnapshotInOf<T> =
  T extends ObjectMap<infer V>
    ? SnapshotInOfObjectMap<V> extends infer R
      ? R
      : never
    : T extends ArraySet<infer V>
      ? SnapshotInOfArraySet<V> extends infer R
        ? R
        : never
      : T extends AnyModel
        ? SnapshotInOfModel<T> extends infer R
          ? R
          : never
        : T extends Frozen<any>
          ? SnapshotInOfFrozen<T> extends infer R
            ? R
            : never
          : T extends object
            ? SnapshotInOfObject<T> extends infer R
              ? R
              : never
            : T