text: 
  export const signIn = (credentials) => {
      return (dispatch, getState, { getFirebase }) => {
          const firebase = getFirebase();
  
          firebase.auth().signInWithEmailAndPassword(
              credentials.email,
              credentials.password
          ).then(() => {
              dispatch({ type: "LOGIN_SUCCESS" });
          }).catch((err) => {
              dispatch({ type: "LOGIN_ERROR", err });
          });
      }
  }
  
  export const signOut = () => {
      return (dispatch, getState, { getFirebase }) => {
          const firebase = getFirebase();
  
          firebase.auth().signOut().then(() => {
              dispatch({ type: 'SIGNOUT_SUCCESS' })
          })
      }
  }
  
  export const signUp = (newUser) => {
      return (dispatch, getState, { getFirebase, getFirestore }) => {
          const firebase = getFirebase();
          const firestore = getFirestore();
  
          firebase.auth().createUserWithEmailAndPassword(
              newUser.email,
              newUser.password
          ).then((resp) => {
              return firestore.collection('users').doc(resp.user.uid).set({
                  firstName: newUser.firstName,
                  lastName: newUser.lastName,
                  initials: newUser.firstName[0] + newUser.lastName[0]
              })
          }).then(() => {
              dispatch({ type: 'SIGNUP_SUCCESS' })
          }).catch(err => {
              dispatch({ type: 'SIGNUP_ERROR', err })
          })
      }
  }