How to get firebase data to return from a function?-CodePudding

I am trying to get data from firebase Realtime database. I know how to get the data, I can log it, but it is not returning. It always return undefined if I use that function anywhere else in my code to set that data to a variable.


function getData(target) {
  const reference = ref(db, `${target}/`);
  onValue(reference, (snapshot) => {
    if (snapshot.exists()) {
      console.log(snapshot.val());
      return snapshot.val();
    }
  });
}

The console.log(snapshot.val()); works

I tried many solution, but couldn't get it to work the way I want it to be. Basically, I want to get data from firebase and make it function, so that I can use it in my other files, just by passing a database reference. Everything work except it doesn't not return that value.

CodePudding user response：

It sounds like you only want to read data once, which you can do with get() like this:

function getData(target) {
  const reference = ref(db, `${target}/`);
  return get(reference).then((snapshot) => {
    if (snapshot.exists()) {
      return snapshot.val();
    }
    // TODO: what do you want to return when the snapshot does *not* exist?
  });
}

Or with async/await

async function getData(target) {
  const reference = ref(db, `${target}/`);
  const snapshot = get(reference);
  if (snapshot.exists()) {
    return snapshot.val();
  }
  // TODO: what do you want to return when the snapshot does *not* exist?
}