Function createIterableMethod

packages/reactivity/src/collectionHandlers.ts:33–75

(
  method: string | symbol,
  isReadonly: boolean,
  isShallow: boolean,
)

  Reflect.getPrototypeOf(v)

function createIterableMethod(
  method: string | symbol,
  isReadonly: boolean,
  isShallow: boolean,
) {
  return function (
    this: IterableCollections,
    ...args: unknown[]
  ): Iterable<unknown> & Iterator<unknown> {
    const target = this[ReactiveFlags.RAW]
    const rawTarget = toRaw(target)
    const targetIsMap = isMap(rawTarget)
    const isPair =
      method === 'entries' || (method === Symbol.iterator && targetIsMap)
    const isKeyOnly = method === 'keys' && targetIsMap
    const innerIterator = target[method](...args)
    const wrap = isShallow ? toShallow : isReadonly ? toReadonly : toReactive
    !isReadonly &&
      track(
        rawTarget,
        TrackOpTypes.ITERATE,
        isKeyOnly ? MAP_KEY_ITERATE_KEY : ITERATE_KEY,
      )
    // return a wrapped iterator which returns observed versions of the
    // values emitted from the real iterator
    return extend(
      // inheriting all iterator properties
      Object.create(innerIterator),
      {
        // iterator protocol
        next() {
          const { value, done } = innerIterator.next()
          return done
            ? { value, done }
            : {
                value: isPair ? [wrap(value[0]), wrap(value[1])] : wrap(value),
                done,
              }
        },
      },
    )
  }
}

function createReadonlyMethod(type: TriggerOpTypes): Function {
  return function (this: CollectionTypes, ...args: unknown[]) {