Promise.所有返回 function

Question

I would like use Async/Await with fetch API. So, i've 2 async function for return result.json() .

I add my 2 Promise in Promise.all([]) , but the values returned is 'function()'.

My code:

  // Load external users
  const externalUsers = async () => {
    const result = await fetch(url);
    return result.json();
  };

  const localUsers = async () => {
    const result = await Users.allDocs({ include_docs: true });
    return result.rows;
  };

  Promise.all([externalUsers, localUsers]).then(values => {
    console.log(values); // return (2) [function, function]
  });

I don't understand why. Can you help me?

Thank you community !

Answer 1

Run your functions in the Promise.all . So they will return Promises which will be settled and passed to the then function.

Promise.all([externalUsers(), localUsers()]).then(values => {
    console.log(values);
});

Answer 2

You should await your Promise.all

const values = await Promise.all([...]);
const value1 = values[0];
...

The reason you are seeing functions, is because Promise.all returns a Promise that resolves to an array. So by await ing the Promise.all , you wait for them all to finish/resolve first.

Answer 3

You can also do,

const [externalUsersResult, localUsersResult] = await Promise.all([externalUsers, localUsers])