I want to implement a code to retrieve data from firestore collection
I use typescript as a programming language. But found an error while following the existing example, while the example uses javascript
the error occured at setBookmark(querySnapshot.forEach((doc) => {
React.useEffect(() => {
const getBookmark = async () => {
try {
const querySnapshot = await getDocs(collection(db, "bookmark"));
setBookmark(querySnapshot.forEach((doc) => {
id: doc.id,
data: doc.data()
// console.log(`${doc.id} => ${doc.data()}`);
}));
} catch (e) {
console.error("Error getting document: ", e);
}
};
getBookmark();
}, []);
forEach returns void hence the error. I think you want to use .map instead. Your current would always set setBookmark(null). I would write the code for you but its not clear what goes into bookmark.
map will return a new list based on the old list while forEach is to just iterate and not returning anything.
As I remember, you can't use map with querySnapshot, but you can create an array from it.
const myArray = [];
querySnapshot.forEach((doc) => {
myArray.push({
id: doc.id,
data: doc.data()
})
setBookmark(myArray)