手写 Promise.all/race/allSettled/any

// 有一个失败则返回失败的结果，全部成功返回全成功的数组
Promise.all = function (promiseList = []) {
  return new Promise((resolve, reject) => {
    const result = []
    let count = 0
    if (promiseList.length === 0) {
      resolve(result)
      return
    }
    for (let i = 0; i < promiseList.length; i++) {
      Promise.resolve(promiseList[i]).then(res => {
        result[i] = res
        count++
        if (count === promiseList.length) {
          resolve(result)
        }
      }).catch(e => {
        reject(e)
      })
    }
  })
}
// 返回第一个成功或失败的结果
Promise.race = function (promiseList = []) {
  return new Promise((resolve, reject) => {
    if (promiseList.length === 0) {
      return resolve([])
    }
    for (let i = 0; i < promiseList.length; i++) {
      Promise.resolve(promiseList[i]).then(res => {
        resolve(res)
      }).catch(e => {
        reject(e)
      })
    }
  })
}
// 无论成功约否都返回，但是会添加一个 status 字段用于标记成功/失败
Promise.allSettled = function (promiseList = []) {
  return new Promise((resolve, reject) => {
    const result = []
    let count = 0

    const addRes = (i, data) => {
      result[i] = data
      count++
      if (count === promiseList.length) {
        resolve(result)
      }
    }
    
    if (promiseList.length === 0) return resolve(result)
    for (let i = 0; i < promiseList.length; i++) {
      Promise.resolve(promiseList[i]).then(res => {
        addRes(i, { status: 'fulfilled', data: res })
      }).catch(e => {
        addRes(i, { status: 'rejected', data: e })
      })
    }
  })
}
// 和 Promise.all 相反，全部失败返回失败的结果数组，有一个成功则返回成功结果
Promise.any = function (promiseList = []) {
  return new Promise((resolve, reject) => {
    if (promiseList.length === 0) return resolve([])
    let count = 0
    const result = []
    for (let i = 0; i < promiseList.length; i++) {
      Promise.resolve(promiseList[i]).then(res => {
        resolve(res)
      }).catch(e => {
        count++
        result[i] = e
        if (count === promiseList.length) {
          reject(new AggregateError(result))
        }
      })
    }
  })
}