javascript 与异步等待的承诺

Posted 2021-05-04

const fetchData = ((id) => {
    let candidate = [{ "name": "Jamal", "age": "29", "gender": "male"},
                      { "name": "Sandra", "age": "21", "gender": "remale"},
                        { "name": "Greg", "age": "29", "gender": "male"}]
    return new Promise((resolve, reject) => {
      setTimeout(() => {
          if (id !== undefined && id <= candidate.length -1) {
            resolve(candidate[id])
          } else {
            reject("Ooops!, user not found: You must provide a valid userId")
          }
      }, 1000)
  }) 
})
  
  
  async function dataCall2(userId) {
   const candidate = await fetchData(userId)
     for (var key in candidate) {
         if (candidate.hasOwnProperty(key)) {
            console.log(key.toUpperCase() + ": " + candidate[key])
         } 
     }
  }
  
 dataCall2(2).catch(e => {
     console.log(e)
 })