Para começar com o Cloud Firestore

import { initializeApp } from "firebase/app";
import { getFirestore } from "firebase/firestore";

// TODO: Replace the following with your app's Firebase project configuration
// See: https://support.google.com/firebase/answer/7015592
const firebaseConfig = {
    FIREBASE_CONFIGURATION
};

// Initialize Firebase
const app = initializeApp(firebaseConfig);


// Initialize Cloud Firestore and get a reference to the service
const db = getFirestore(app);

import firebase from "firebase/app";
import "firebase/firestore";

// TODO: Replace the following with your app's Firebase project configuration
// See: https://support.google.com/firebase/answer/7015592
const firebaseConfig = {
    FIREBASE_CONFIGURATION
};

// Initialize Firebase
firebase.initializeApp(firebaseConfig);


// Initialize Cloud Firestore and get a reference to the service
const db = firebase.firestore();

import FirebaseCore
import FirebaseFirestore

FirebaseApp.configure()

let db = Firestore.firestore()
AppDelegate.swift

@import FirebaseCore;
@import FirebaseFirestore;

// Use Firebase library to configure APIs
[FIRApp configure];
  

FIRFirestore *defaultFirestore = [FIRFirestore firestore];
AppDelegate.m

// Access a Cloud Firestore instance from your Activity

val db = Firebase.firestore
DocSnippets.kt

// Access a Cloud Firestore instance from your Activity

FirebaseFirestore db = FirebaseFirestore.getInstance();
DocSnippets.java

db = FirebaseFirestore.instance;

// Make sure the call to `Create()` happens some time before you call Firestore::GetInstance().
App::Create();
Firestore* db = Firestore::GetInstance();
AppDelegate.mm

using Firebase.Firestore;
using Firebase.Extensions;

FirebaseFirestore db = FirebaseFirestore.DefaultInstance;

import { collection, addDoc } from "firebase/firestore"; 

try {
  const docRef = await addDoc(collection(db, "users"), {
    first: "Ada",
    last: "Lovelace",
    born: 1815
  });
  console.log("Document written with ID: ", docRef.id);
} catch (e) {
  console.error("Error adding document: ", e);
}
add_ada_lovelace.js

db.collection("users").add({
    first: "Ada",
    last: "Lovelace",
    born: 1815
})
.then((docRef) => {
    console.log("Document written with ID: ", docRef.id);
})
.catch((error) => {
    console.error("Error adding document: ", error);
});
test.firestore.js

// Add a new document with a generated ID
do {
  let ref = try await db.collection("users").addDocument(data: [
    "first": "Ada",
    "last": "Lovelace",
    "born": 1815
  ])
  print("Document added with ID: \(ref.documentID)")
} catch {
  print("Error adding document: \(error)")
}
ViewController.swift

// Add a new document with a generated ID
__block FIRDocumentReference *ref =
    [[self.db collectionWithPath:@"users"] addDocumentWithData:@{
      @"first": @"Ada",
      @"last": @"Lovelace",
      @"born": @1815
    } completion:^(NSError * _Nullable error) {
      if (error != nil) {
        NSLog(@"Error adding document: %@", error);
      } else {
        NSLog(@"Document added with ID: %@", ref.documentID);
      }
    }];
ViewController.m

// Create a new user with a first and last name
val user = hashMapOf(
    "first" to "Ada",
    "last" to "Lovelace",
    "born" to 1815,
)

// Add a new document with a generated ID
db.collection("users")
    .add(user)
    .addOnSuccessListener { documentReference ->
        Log.d(TAG, "DocumentSnapshot added with ID: ${documentReference.id}")
    }
    .addOnFailureListener { e ->
        Log.w(TAG, "Error adding document", e)
    }
DocSnippets.kt

// Create a new user with a first and last name
Map<String, Object> user = new HashMap<>();
user.put("first", "Ada");
user.put("last", "Lovelace");
user.put("born", 1815);

// Add a new document with a generated ID
db.collection("users")
        .add(user)
        .addOnSuccessListener(new OnSuccessListener<DocumentReference>() {
            @Override
            public void onSuccess(DocumentReference documentReference) {
                Log.d(TAG, "DocumentSnapshot added with ID: " + documentReference.getId());
            }
        })
        .addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                Log.w(TAG, "Error adding document", e);
            }
        });
DocSnippets.java

// Create a new user with a first and last name
final user = <String, dynamic>{
  "first": "Ada",
  "last": "Lovelace",
  "born": 1815
};

// Add a new document with a generated ID
db.collection("users").add(user).then((DocumentReference doc) =>
    print('DocumentSnapshot added with ID: ${doc.id}'));
firestore.dart

// Add a new document with a generated ID
Future<DocumentReference> user_ref =
    db->Collection("users").Add({{"first", FieldValue::String("Ada")},
                                 {"last", FieldValue::String("Lovelace")},
                                 {"born", FieldValue::Integer(1815)}});

user_ref.OnCompletion([](const Future<DocumentReference>& future) {
  if (future.error() == Error::kErrorOk) {
    std::cout << "DocumentSnapshot added with ID: " << future.result()->id()
              << std::endl;
  } else {
    std::cout << "Error adding document: " << future.error_message() << std::endl;
  }
});
snippets.cpp

DocumentReference docRef = db.Collection("users").Document("alovelace");
Dictionary<string, object> user = new Dictionary<string, object>
{
	{ "First", "Ada" },
	{ "Last", "Lovelace" },
	{ "Born", 1815 },
};
docRef.SetAsync(user).ContinueWithOnMainThread(task => {
	Debug.Log("Added data to the alovelace document in the users collection.");
});

// Add a second document with a generated ID.
import { addDoc, collection } from "firebase/firestore"; 

try {
  const docRef = await addDoc(collection(db, "users"), {
    first: "Alan",
    middle: "Mathison",
    last: "Turing",
    born: 1912
  });

  console.log("Document written with ID: ", docRef.id);
} catch (e) {
  console.error("Error adding document: ", e);
}
add_alan_turing.js

// Add a second document with a generated ID.
db.collection("users").add({
    first: "Alan",
    middle: "Mathison",
    last: "Turing",
    born: 1912
})
.then((docRef) => {
    console.log("Document written with ID: ", docRef.id);
})
.catch((error) => {
    console.error("Error adding document: ", error);
});
test.firestore.js

// Add a second document with a generated ID.
do {
  let ref = try await db.collection("users").addDocument(data: [
    "first": "Alan",
    "middle": "Mathison",
    "last": "Turing",
    "born": 1912
  ])
  print("Document added with ID: \(ref.documentID)")
} catch {
  print("Error adding document: \(error)")
}
ViewController.swift

// Add a second document with a generated ID.
__block FIRDocumentReference *ref =
    [[self.db collectionWithPath:@"users"] addDocumentWithData:@{
      @"first": @"Alan",
      @"middle": @"Mathison",
      @"last": @"Turing",
      @"born": @1912
    } completion:^(NSError * _Nullable error) {
      if (error != nil) {
        NSLog(@"Error adding document: %@", error);
      } else {
        NSLog(@"Document added with ID: %@", ref.documentID);
      }
    }];
ViewController.m

// Create a new user with a first, middle, and last name
val user = hashMapOf(
    "first" to "Alan",
    "middle" to "Mathison",
    "last" to "Turing",
    "born" to 1912,
)

// Add a new document with a generated ID
db.collection("users")
    .add(user)
    .addOnSuccessListener { documentReference ->
        Log.d(TAG, "DocumentSnapshot added with ID: ${documentReference.id}")
    }
    .addOnFailureListener { e ->
        Log.w(TAG, "Error adding document", e)
    }
DocSnippets.kt

// Create a new user with a first, middle, and last name
Map<String, Object> user = new HashMap<>();
user.put("first", "Alan");
user.put("middle", "Mathison");
user.put("last", "Turing");
user.put("born", 1912);

// Add a new document with a generated ID
db.collection("users")
        .add(user)
        .addOnSuccessListener(new OnSuccessListener<DocumentReference>() {
            @Override
            public void onSuccess(DocumentReference documentReference) {
                Log.d(TAG, "DocumentSnapshot added with ID: " + documentReference.getId());
            }
        })
        .addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                Log.w(TAG, "Error adding document", e);
            }
        });
DocSnippets.java

// Create a new user with a first and last name
final user = <String, dynamic>{
  "first": "Alan",
  "middle": "Mathison",
  "last": "Turing",
  "born": 1912
};

// Add a new document with a generated ID
db.collection("users").add(user).then((DocumentReference doc) =>
    print('DocumentSnapshot added with ID: ${doc.id}'));
firestore.dart

db->Collection("users")
    .Add({{"first", FieldValue::String("Alan")},
          {"middle", FieldValue::String("Mathison")},
          {"last", FieldValue::String("Turing")},
          {"born", FieldValue::Integer(1912)}})
    .OnCompletion([](const Future<DocumentReference>& future) {
      if (future.error() == Error::kErrorOk) {
        std::cout << "DocumentSnapshot added with ID: "
                  << future.result()->id() << std::endl;
      } else {
        std::cout << "Error adding document: " << future.error_message()
                  << std::endl;
      }
    });
snippets.cpp

DocumentReference docRef = db.Collection("users").Document("aturing");
Dictionary<string, object> user = new Dictionary<string, object>
{
	{ "First", "Alan" },
	{ "Middle", "Mathison" },
	{ "Last", "Turing" },
	{ "Born", 1912 }
};
docRef.SetAsync(user).ContinueWithOnMainThread(task => {
	Debug.Log("Added data to the aturing document in the users collection.");
});

import { collection, getDocs } from "firebase/firestore"; 

const querySnapshot = await getDocs(collection(db, "users"));
querySnapshot.forEach((doc) => {
  console.log(`${doc.id} => ${doc.data()}`);
});
get_all_users.js

db.collection("users").get().then((querySnapshot) => {
    querySnapshot.forEach((doc) => {
        console.log(`${doc.id} => ${doc.data()}`);
    });
});
test.firestore.js

do {
  let snapshot = try await db.collection("users").getDocuments()
  for document in snapshot.documents {
    print("\(document.documentID) => \(document.data())")
  }
} catch {
  print("Error getting documents: \(error)")
}
ViewController.swift

[[self.db collectionWithPath:@"users"]
    getDocumentsWithCompletion:^(FIRQuerySnapshot * _Nullable snapshot,
                                 NSError * _Nullable error) {
      if (error != nil) {
        NSLog(@"Error getting documents: %@", error);
      } else {
        for (FIRDocumentSnapshot *document in snapshot.documents) {
          NSLog(@"%@ => %@", document.documentID, document.data);
        }
      }
    }];
ViewController.m

db.collection("users")
    .get()
    .addOnSuccessListener { result ->
        for (document in result) {
            Log.d(TAG, "${document.id} => ${document.data}")
        }
    }
    .addOnFailureListener { exception ->
        Log.w(TAG, "Error getting documents.", exception)
    }
DocSnippets.kt

db.collection("users")
        .get()
        .addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
            @Override
            public void onComplete(@NonNull Task<QuerySnapshot> task) {
                if (task.isSuccessful()) {
                    for (QueryDocumentSnapshot document : task.getResult()) {
                        Log.d(TAG, document.getId() + " => " + document.getData());
                    }
                } else {
                    Log.w(TAG, "Error getting documents.", task.getException());
                }
            }
        });
DocSnippets.java

await db.collection("users").get().then((event) {
  for (var doc in event.docs) {
    print("${doc.id} => ${doc.data()}");
  }
});
firestore.dart

users_ref = db.collection("users")
docs = users_ref.stream()

for doc in docs:
    print(f"{doc.id} => {doc.to_dict()}")
snippets.py

Future<QuerySnapshot> users = db->Collection("users").Get();
users.OnCompletion([](const Future<QuerySnapshot>& future) {
  if (future.error() == Error::kErrorOk) {
    for (const DocumentSnapshot& document : future.result()->documents()) {
      std::cout << document << std::endl;
    }
  } else {
    std::cout << "Error getting documents: " << future.error_message()
              << std::endl;
  }
});
snippets.cpp

CollectionReference usersRef = db.Collection("users");
usersRef.GetSnapshotAsync().ContinueWithOnMainThread(task =>
{
  QuerySnapshot snapshot = task.Result;
  foreach (DocumentSnapshot document in snapshot.Documents)
  {
    Debug.Log(String.Format("User: {0}", document.Id));
    Dictionary<string, object> documentDictionary = document.ToDictionary();
    Debug.Log(String.Format("First: {0}", documentDictionary["First"]));
    if (documentDictionary.ContainsKey("Middle"))
    {
      Debug.Log(String.Format("Middle: {0}", documentDictionary["Middle"]));
    }

    Debug.Log(String.Format("Last: {0}", documentDictionary["Last"]));
    Debug.Log(String.Format("Born: {0}", documentDictionary["Born"]));
  }

  Debug.Log("Read all data from the users collection.");
});

// Allow read/write access to a document keyed by the user's UID
service cloud.firestore {
  match /databases/{database}/documents {
    match /users/{uid} {
      allow read, write: if request.auth != null && request.auth.uid == uid;
    }
  }
}

// Deny read/write access to all users under any conditions
service cloud.firestore {
  match /databases/{database}/documents {
    match /{document=**} {
      allow read, write: if false;
    }
  }
}