使用Promise.all()优化请求

function fetchBox(param) {  return new Promise((resolve, reject) => {    setTimeout(() => {      let box = {}      box[param] = [1, 2, 3]      resolve(box)    }, 5000);  })}let params = ['apple', 'banana', 'orange']let result = []// 1.不应该每个请求都依次 awaitparams.forEach(async (param) => {  result.push(await fetchBox(param))})// 2.而是将同类的请求放到Promise.all()中去let pool = params.map(param => {  return fetchBox(param)})let promiseResult = Promise.all(pool)console.log(result)console.log(promiseResult)