Here's a Firebase cheatsheet with commonly used features and commands in an Angular application:

Firebase Initialization in Angular

• Install Firebase packages:

npm install firebase @angular/fire

• Import Firebase and initialize it in your Angular app:

import { AngularFireModule } from '@angular/fire';
import { AngularFireAuthModule } from '@angular/fire/auth';
import { AngularFirestoreModule } from '@angular/fire/firestore';
import { AngularFireStorageModule } from '@angular/fire/storage';

const firebaseConfig = {
  apiKey: 'YOUR_API_KEY',
  authDomain: 'YOUR_AUTH_DOMAIN',
  projectId: 'YOUR_PROJECT_ID',
  storageBucket: 'YOUR_STORAGE_BUCKET',
  appId: 'YOUR_APP_ID',
};

@NgModule({
  imports: [
    AngularFireModule.initializeApp(firebaseConfig),
    AngularFireAuthModule,
    AngularFirestoreModule,
    AngularFireStorageModule,
    // other imports
  ],
  // other configurations
})
export class AppModule { }

Authentication in Angular

import { AngularFireAuth } from '@angular/fire/auth';

constructor(private afAuth: AngularFireAuth) {}

// Sign up with email and password
this.afAuth.createUserWithEmailAndPassword(email, password)
  .then((userCredential) => {
    // User creation successful
    const user = userCredential.user;
  })
  .catch((error) => {
    // An error occurred
    const errorCode = error.code;
    const errorMessage = error.message;
  });

// Sign in with email and password
this.afAuth.signInWithEmailAndPassword(email, password)
  .then((userCredential) => {
    // User authentication successful
    const user = userCredential.user;
  })
  .catch((error) => {
    // An error occurred
    const errorCode = error.code;
    const errorMessage = error.message;
  });

// Sign out
this.afAuth.signOut()
  .then(() => {
    // User signed out successfully
  })
  .catch((error) => {
    // An error occurred
  });

// Get the currently signed-in user
this.afAuth.user.subscribe((user) => {
  if (user) {
    // User is signed in
    const uid = user.uid;
  } else {
    // User is signed out
  }
});

Firestore (Database) in Angular

import { AngularFirestore } from '@angular/fire/firestore';

constructor(private firestore: AngularFirestore) {}

// Get a reference to a collection
const collectionRef = this.firestore.collection('collectionName');

// Add a document to a collection
collectionRef.add({ key: 'value' })
  .then((docRef) => {
    // Document added successfully
    const documentId = docRef.id;
  })
  .catch((error) => {
    // An error occurred
  });

// Update a document
collectionRef.doc('documentId').update({ key: 'value' })
  .then(() => {
    // Document updated successfully
  })
  .catch((error) => {
    // An error occurred
  });

// Delete a document
collectionRef.doc('documentId').delete()
  .then(() => {
    // Document deleted successfully
  })
  .catch((error) => {
    // An error occurred
  });

// Get a document
collectionRef.doc('documentId').get()
  .subscribe((doc) => {
    if (doc.exists) {
      // Document data exists
      const documentData = doc.data();
    } else {
      // Document doesn't exist
    }
  }, (error) => {
    // An error occurred
  });

// Query documents in a collection
collectionRef.where('field', '==', 'value').get()
  .subscribe((querySnapshot) => {
    querySnapshot.forEach((doc) => {
      // Access each document
      const documentData = doc.data();
    });
  }, (error) => {
    // An error occurred
  });

Storage in Angular

import { AngularFireStorage } from '@angular/fire/storage';

constructor(private storage: AngularFireStorage) {}

// Get a reference to a file in storage
const fileRef = this.storage.ref('path/to/file.jpg');

// Upload a file
fileRef.put(file)
  .then((snapshot) => {
    // File uploaded successfully
    const downloadUrl = snapshot.ref.getDownloadURL();
  })
  .catch((error) => {
    // An error occurred
  });

// Download a file
fileRef.getDownloadURL()
  .subscribe((downloadUrl) => {
    // File download URL obtained successfully
  }, (error) => {
    // An error occurred
  });

// Delete a file
fileRef.delete()
  .then(() => {
    // File deleted successfully
  })
  .catch((error) => {
    // An error occurred
  });

This cheatsheet provides an overview of using Firebase features in an Angular application. Remember to install the necessary packages and import the required modules in your Angular app.