Return a value asynchronously with react native

Question

I created a function in react-native that looks like this one

static async myFunction(){
  await RNSFAuthenticationSession.getSafariData(url,scheme).then(async (callbackUrl) => {
    const isValid = await MyClass.checkIfValid(data);
    if (isValid) {
      return true;
    } else {
      return false;
    }
}

and I am calling it in this way

const isValid = await MyClass.myFunction();
alert(isValid); // undefined

isValid contains an undefined value. Do you know how can I fix this?

`await` does not automatically make a callback method into a Promise, you will need to make `getSafariData` into a Promise. — Keith, Jan 22 '18 at 13:02
Possible Duplicate [How do I return the response from an asynchronous call?](https://stackoverflow.com/questions/14220321/how-do-i-return-the-response-from-an-asynchronous-call) — Mayank Shukla, Jan 22 '18 at 13:05

score 1 · Answer 1 · answered Jan 22 '18 at 13:03

You forgot to return Promise

static async myFunction(){
   return await RNSFAuthenticationSession.getSafariData(url,scheme).then(async (callbackUrl) => {
   const isValid = await MyClass.checkIfValid(data);
   if (isValid){
      return true;
   } else {
      return false;
   }
}

and you can simplify your code

static myFunction() {
   return RNSFAuthenticationSession.getSafariData(url, scheme)
      .then(() => MyClass.checkIfValid(data))
}

Return a value asynchronously with react native

1 Answers1