effect.ts

interface OnStop {
  onStop: () => void;
}

interface ReactiveEffectOption {
  scheduler: () => void;
}

interface Runner {
  effect: ReactiveEffect;
  (): void;
}

type ReactiveEffectOptionKey = keyof ReactiveEffectOption

class ReactiveEffectOptionValue {
  constructor(private options: Partial<ReactiveEffectOption> = {}) { }
  get<T extends ReactiveEffectOptionKey>(key: T, defaultValue?: ReactiveEffectOption[T]): ReactiveEffectOption[T] | undefined {
    return this.options?.[key] ?? defaultValue
  }
}

export class ReactiveEffect<T extends Function = Function> {
  /**当前effect */
  static activeEffect: ReactiveEffect | undefined = undefined
  /**是否应该track的标记 */
  // static shouldTrack = true
  /**是否可以track */
  // static get isTrackable() {
  //   return ReactiveEffect.shouldTrack && ReactiveEffect.activeEffect !== undefined
  // }

  // static cleanup(effect: ReactiveEffect) {
  //   if (ReactiveEffect.activeEffect) {
  //     for (const deps of effect.deps) {
  //       deps.delete(effect)
  //     }
  //     effect.deps = []
  //   }
  // }

  deps: Array<Set<ReactiveEffect>> = []
  active = true
  _onStop?: () => void

  constructor(private fn: T, private _options: Partial<ReactiveEffectOption> = {}) { }
  get options() {
    return new ReactiveEffectOptionValue(this._options)
  }
  set onStop(fn: (() => void) | undefined) {
    this._onStop = fn
  }
  run() {
    // if (!this.active) {
    //   return this.fn()
    // }
    // ReactiveEffect.shouldTrack = true
    ReactiveEffect.activeEffect = this
    const res = this.fn()
    // ReactiveEffect.shouldTrack = false
    return res
  }

  // stop() {
  //   ReactiveEffect.cleanup(this)
  //   this._onStop?.()
  //   this.active = false
  // }
}

export function effect<T extends Function>(fn: T, options?: Partial<ReactiveEffectOption & OnStop>) {
  // 分解options
  const { onStop, ...EffectOptions } = options ?? {}
  const _effect = new ReactiveEffect(fn, EffectOptions)
  // _effect.onStop = onStop
  _effect.run()

  const runner = (() => {
    _effect.run()
  }) as Runner
  runner.effect = _effect
  return runner
}

// export function stop(effect: ReactiveEffect) {
//   effect.stop()
// }