mobx-keystone/src/dataModel/utils.ts

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

import type { ModelClass } from "../modelShared/BaseModelShared"
import { failure } from "../utils"
import type { AnyDataModel } from "./BaseDataModel"
import { BaseDataModel } from "./BaseDataModel"

/**
 * Checks if an object is a data model instance.
 *
 * @param model
 * @returns
 */
export function isDataModel(model: unknown): model is AnyDataModel {
  return model instanceof BaseDataModel
}

/**
 * @internal
 *
 * Asserts something is actually a data model.
 *
 * @param model
 * @param argName
 */
export function assertIsDataModel(
  model: unknown,
  argName: string,
  customErrMsg = "must be a data model instance"
): asserts model is AnyDataModel {
  if (!isDataModel(model)) {
    throw failure(`${argName} ${customErrMsg}`)
  }
}

/**
 * @internal
 */
export function isDataModelClass(modelClass: unknown): modelClass is ModelClass<AnyDataModel> {
  if (typeof modelClass !== "function") {
    return false
  }

  if (modelClass !== BaseDataModel && !(modelClass.prototype instanceof BaseDataModel)) {
    return false
  }

  return true
}

/**
 * @internal
 */
export function assertIsDataModelClass(
  modelClass: unknown,
  argName: string
): asserts modelClass is ModelClass<AnyDataModel> {
  if (typeof modelClass !== "function") {
    throw failure(`${argName} must be a class`)
  }

  if (modelClass !== BaseDataModel && !(modelClass.prototype instanceof BaseDataModel)) {
    throw failure(`${argName} must extend DataModel`)
  }
}