Question

187

How to get a single doc with React/Firestore?

rated 0 times [ 188] [ 1] / answers: 1 / hits: 9147 / 3 Years ago, sun, april 25, 2021, 12:00:00

All I want to do is to get a row (so called 'doc') from a data base.

so far, I have tried:

all with the 'aref'

  const aref = firebase

    .firestore()

    .collection("polja")

    .where("id", "==", match.params.id);

  console.log(aref);



  function getIt() {

    const item = [];

    setLoading(true);

    aref.get().then((doc) => {

      const data = doc.data();

      setItem(item);

      console.log(item);

      setLoading(false);

    });

  }

  

  useEffect(() => {

    getIt();

  }, []);

this gave the following error:

error

Answers

Only authorized users can answer the question. Please sign in first, or register a free account.

luna

Add To Favorites

Follow

Total Points: 698

Total Questions: 114

Total Answers: 93

Location: Israel

Member since Wed, Apr 14, 2021

3 Years ago

luna questions

1 TypeError: Cannot read properties of null (reading 'classList')

Tue, Dec 7, 21, 00:00, 3 Years ago

1 None of these files exist

Sun, Jul 11, 21, 00:00, 3 Years ago

1 How to test failed request with axios / jest

Wed, Jun 30, 21, 00:00, 3 Years ago

1 Howler.js - The AudioContext was not allowed to start. It must be resumed (or created) after a user gesture on the page

Tue, May 25, 21, 00:00, 3 Years ago

1 How vue.js cli command npm run serve work

Tue, Oct 13, 20, 00:00, 4 Years ago

View All

answered 3 Years ago michelecarissab · Accepted Answer

To get a single document, you must specify the document ID:

firebase.firestore().collection("polja").doc(documentId).get().then((snapshot) => {

  console.log(snapshot.data())

}).catch((e) => console.log(e))

Also you should not use .where() to get just a single document, but there is an issue I found in your original code.

If you look carefully, the parameter in .where() is a string "match.params.id". That seems to be a dynamic value being fetched from somewhere else. Please remove the quotes and try again.

firebase.firestore().collection("polja").where("id", "==", match.params.id).get()

    .then((querySnapshot) => {

        querySnapshot.forEach((doc) => {

            // doc.data() is never undefined for query doc snapshots

            console.log(doc.id, " => ", doc.data());

        });

    })

    .catch((error) => {

        console.log("Error getting documents: ", error);

    });

Try adding a catch block as shown which might help catch any errors. Make sure your security rules also allow you to fetch the data.
Also if any error is logged in the console, share a screenshot of it.