mobx-keystone/src/action/applySet.ts

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

import { isObservable } from "mobx"
import { isModel } from "../model/utils"
import { assertTweakedObject } from "../tweaker/core"
import { lazy } from "../utils"
import { setIfDifferent } from "../utils/setIfDifferent"
import { BuiltInAction } from "./builtInActions"
import { ActionContextActionType } from "./context"
import { wrapInAction } from "./wrapInAction"

/**
 * Sets an object field wrapped in an action.
 *
 * @param node  Target object.
 * @param fieldName Field name.
 * @param value Value to set.
 */
export function applySet<O extends object, K extends keyof O, V extends O[K]>(
  node: O,
  fieldName: K,
  value: V
): void {
  assertTweakedObject(node, "node", true)

  wrappedInternalApplySet().call(node, fieldName as string | number, value)
}

function internalApplySet<O extends object>(this: O, fieldName: string | number, value: any): void {
  // we need to check if it is a model since models can become observable objects
  // (e.g. by having a computed value)
  if (!isModel(this) && isObservable(this)) {
    setIfDifferent(this, fieldName, value)
  } else {
    ;(this as any)[fieldName] = value
  }
}

const wrappedInternalApplySet = lazy(() =>
  wrapInAction({
    nameOrNameFn: BuiltInAction.ApplySet,
    fn: internalApplySet,
    actionType: ActionContextActionType.Sync,
  })
)