chain-of-responsibility-in-java-script_8.js

class CumulativeSum {
  constructor() {
    this._executor = null
  }

  get executor() {
    if (!this._executor) return (val) => val
    return this._executor
  }

  set executor(fn) {
    this._executor = fn
  }

  async add(currentValue) {
    const result = await this.executor(currentValue, async (nextVal) => {
      if (this.next) return this.next.add(nextVal)
      return nextVal
    })
    return result
  }
}