File example for medium article

mediumAjaxFirestoreCall.js

  firebase.initializeApp({
      apiKey: "YOUR apiKey",
      authDomain: "YOUR authDomain",
      projectId: "YOUR projectId",
  });

  let firestore = firebase.firestore();
  let collection = firestore.collection('Teste');

  collection.get().then(result => {
    console.log(result.size)
  }).catch((err) => {
    console.log('Erro !'+err);
  });