javascript - Promise { } ' why is it still pending?' 我该如何解决这个问题？

Question

因此控制台中的结果显示为 -

Promise { <pending> } ' why is it still pending?'
[ { _id: 5a7c6552380e0a299fa752d3, username: 'test', score: 44 } ]

所以它告诉我 Promise { pending } 但随后是我想看到的答案 -

[ { _id: 5a7c6552380e0a299fa752d3, username: 'test', score: 44 } ]

但是我该如何修复那个 promise pending 部分，它是我在代码底部运行的 console.log。

function resolveAfter1() {
  return new Promise((resolve, reject) => {
    var scoresFromDb = db.account.find({}, { username: 1, score: 1 }).toArray(function(err, result) {
          if (err) 
              reject(err);
          else
              resolve(result);
    });
  });
}

resolveAfter1() // resolve function
    .then((result)=>{console.log(result);})
    .catch((error)=>{console.log(error);})

    async function asyncCall() {
      var result = await resolveAfter1();
      // console.log(result);
    }

    console.log(asyncCall(), ' why is it still pending?');

Answer 1

替换:

console.log(asyncCall(), ' why is it still pending?');

与:

async function run() {
   console.log(await asyncCall());
}

run();

您正在打印 asyncCall 的结果，这是一个 async function。异步函数将返回的结果包装在 Promise 中，如果您想要 Promise 解析到的实际值，则必须使用 await someAsyncFunc()。

举个简单的例子:

async function asyncCall() {
   return 1;
}

async function run() {
   console.log(asyncCall()); // this doesn't wait for the Promise to resolve
   console.log(await asyncCall()); // this does
}

run();