Function that returns a URL value

Question

How would I transform this function so that instead of sending the date value to prepareListDados() when called, it returns this date value when called in prepareListDados()

const getDados = async () => {
  let url = 'http://' + host + '/dados';
  xhttp.onreadystatechange = () => {
      if (xhttp.readyState == 4 && xhttp.status == 200) {
          var data = xhttp.responseText;
          prepareListDados(data);
      }
  }
  await xhttp.open("GET", url, true);
  await xhttp.send();
}

as an example:

const prepareListDados = () =>{
let dados = getDados();
}

so the date value would be in my variable data in the prepareListDados function();

edit1:

const getDadosAsync = () => new Promise((resolve, reject) => {
  let url = 'http://' + host + '/dados';
  xhttp.onreadystatechange = () => {
    if (xhttp.readyState == 4 && xhttp.status == 200) {
      var data = xhttp.responseText;
      resolve(data);
    }
  }
  xhttp.open("GET", url, true);
  xhttp.send();
});

const prepareListDados = async () => new Promise((resolve, reject) => {
    let dados = await getDadosAsync();
    resolve(dados)
});

const setList = async () => {
 let dados = await prepareListDados();
}

something like that

Answer 1

Return a Promise, and call the resolve of the granted value, which will be obtained when you use await.

const getDadosAsync = () => new Promise((resolve, reject) => {
  let url = 'http://' + host + '/dados';
  xhttp.onreadystatechange = () => {
    if (xhttp.readyState == 4 && xhttp.status == 200) {
      var data = xhttp.responseText;
      resolve(data);
    }
  }
  xhttp.open("GET", url, true);
  xhttp.send();
})

const prepareListDadosAsync = async () => {
  let dados = await getDadosAsync();
}

An even easier way to do this is by using fetch, that already returns a default file:

const getDadosAsync = async () => {
  let response = await fetch('http://' + host + '/dados');
  return await response.text();
}

const prepareListDadosAsync = async () => {
  let dados = await getDadosAsync();
}