mobx-keystone/src/parent/core.ts

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

import { createAtom, IAtom } from "mobx"
import { isModel } from "../model/utils"
import { getOrCreate } from "../utils/mapUtils"
import type { ParentPath } from "./path"

/**
 * @internal
 */
export const objectParents = new WeakMap<object, ParentPath<object> | undefined>()

const objectParentsAtoms = new WeakMap<object, IAtom>()

/**
 * @internal
 */
export function parentPathEquals(
  parentPath1: ParentPath<any> | undefined,
  parentPath2: ParentPath<any> | undefined
) {
  if (!(parentPath1 || parentPath2)) {
    return true
  }
  if (!(parentPath1 && parentPath2)) {
    return false
  }
  return parentPath1.parent === parentPath2.parent && parentPath1.path === parentPath2.path
}

function createParentPathAtom() {
  return createAtom("parentAtom")
}

/**
 * @internal
 */
export function reportParentPathObserved(node: object) {
  getOrCreate(objectParentsAtoms, node, createParentPathAtom).reportObserved()
}

/**
 * @internal
 */
export function reportParentPathChanged(node: object) {
  objectParentsAtoms.get(node)?.reportChanged()
}

/**
 * @internal
 */
export const dataObjectParent = new WeakMap<object, object>()

/**
 * @internal
 */
export function dataToModelNode<T extends object>(node: T): T {
  const modelNode = dataObjectParent.get(node)
  return (modelNode as T | undefined) ?? node
}

/**
 * @internal
 */
export function modelToDataNode<T extends object>(node: T): T {
  return isModel(node) ? node.$ : node
}