Function shallowReadonly

src/reactivity/readonly.ts:56–107

(obj: any)

export function shallowReadonly<T extends object>(obj: T): Readonly<T>
export function shallowReadonly(obj: any): any {
  if (!isObject(obj)) {
    if (__DEV__) {
      warn(`value cannot be made reactive: ${String(obj)}`)
    }
    return obj
  }

  if (
    !(isPlainObject(obj) || isArray(obj)) ||
    (!Object.isExtensible(obj) && !isRef(obj))
  ) {
    return obj
  }

  const readonlyObj = isRef(obj)
    ? new RefImpl({} as any)
    : isReactive(obj)
    ? observe({})
    : {}
  const source = reactive({})
  const ob = (source as any).__ob__

  for (const key of Object.keys(obj)) {
    let val = obj[key]
    let getter: (() => any) | undefined
    const property = Object.getOwnPropertyDescriptor(obj, key)
    if (property) {
      if (property.configurable === false && !isRef(obj)) {
        continue
      }
      getter = property.get
    }

    proxy(readonlyObj, key, {
      get: function getterHandler() {
        const value = getter ? getter.call(obj) : val
        ob.dep.depend()
        return value
      },
      set(v: any) {
        if (__DEV__) {
          warn(`Set operation on key "${key}" failed: target is readonly.`)
        }
      },
    })
  }

  readonlySet.set(readonlyObj, true)

  return readonlyObj
}