Function read

packages/effect/src/unstable/reactivity/Atom.ts:1201–1229

(
    get: AtomContext,
    services?: Context.Context<any>
  )

    : undefined

  function read(
    get: AtomContext,
    services?: Context.Context<any>
  ): AsyncResult.AsyncResult<A, E | Cause.NoSuchElementError> {
    const fibers = fibersAtom ? get(fibersAtom) : undefined
    ;(get as any).isFn = true
    const [counter, arg] = get.get(argAtom)
    if (counter === 0) {
      return initialValue
    } else if (arg === Interrupt) {
      return AsyncResult.failureWithPrevious(Cause.interrupt(), { previous: get.self() })
    }
    let value = f(arg, get)
    if (EffectTypeId in value) {
      if (fibers) {
        const eff = value as Effect.Effect<A, E, Scope.Scope | AtomRegistry>
        value = Effect.flatMap(
          Effect.forkDetach(eff, { startImmediately: true }),
          (fiber) => {
            fibers.add(fiber)
            fiber.addObserver(() => fibers.delete(fiber))
            return Effect.map(Fiber.joinAll(fibers), (arr) => arr[0])
          }
        )
      }
      return makeEffect(get, value as any, initialValue, services, false)
    }
    return makeStream(get, value as any, initialValue, services)
  }
  function write(
    ctx: WriteContext<AsyncResult.AsyncResult<A, E | Cause.NoSuchElementError>>,
    arg: Arg | Reset | Interrupt