useState in React Native fails to mount new value?

Trying to retrieve a list of numbers for which will be used later on to retrieve more data.

const [listData, setList] = React.useState();

  let tempSim = Temp();

  const setLog = async() => {
    const array = [];
    const date = getDate();
    const dbCon = database.ref('Conditions/Log/Temp/' + date);
    await dbCon.get().then((snapshot => {
      snapshot.forEach(data => {

The array prints fine with all the correct data, however as soon as I set the state and try print that the only output I've been able to get is undefined?

How many English words
do you know?
Test your English vocabulary size, and measure
how many words do you know
Online Test
Powered by Examplum