Trying to test firestore with JEST, error: TypeError: (0 , _firestore.default) is not a function

[ildaneta]

How to test the library methods with JEST? Like `firestore()``

I'm going crazy trying to test methods like collections, but I can't test it, could someone help me please?

export const checkExistingPhoneNumberUsersCollectionFS = async (
    phoneNumber: string,
): Promise<IUserData[] | []> => {

    const snapshot = await firestore()
      .collection('users')
      .where('phone_number', '==', phoneNumber)
      .get();

    if (instant.empty) {
      return [];
    } other {
      const data = snapshot.docs.map(doc => {
        const {
          uid,
          phone number,
          device_uuid,
          Device Information,
          is_notifications_accepted,
        } = doc.data() as FirebaseFirestoreTypes.DocumentData;

        turn back {
          uid,
          device_uuid,
          phone number,
          Device Information,
          is_notifications_accepted,
        };
      });

      return data;
    }
};

This is the method that checks within the user collection if the number passed exists.

I tried to mock like:

jest.mock('@react-native-firebase/firestore', () => {});

jest.mock('@react-native-firebase/app', () => ({
  firestore: jest.fn(() => ({
    collection: jest.fn(() => ({
      where: jest.fn().mockReturnThis(),
      get: jest.fn().mockResolvedValue({
        empty: true,
        docs: [],
      }),
    })),
  })),
}));

[TM-TerryDutton]

Might be worth double-checking how you're importing the firestore function (since the import isn't shown in your sample code). Your mock defines 'firestore' as a property on an object, but returns the object as the module reference, so if your import doesn't destructure it you'll be trying to call the object instead of the function. If the imported module reference is itself meant to be callable, you'll need to refactor your mock so it returns a function instead of an object.

[ildaneta]

thanks for your reply @TM-TerryDutton, I apologize to not have included the completed code, here it is

import firestore, {
  FirebaseFirestoreTypes,
} from '@react-native-firebase/firestore';
import { IUserData } from '../../types/users';

export const checkExistingPhoneNumberUsersCollectionFS = async (
  phoneNumber: string,
): Promise<IUserData[] | []> => {
  const snapshot = await firestore()
    .collection('users')
    .where('phone_number', '==', phoneNumber)
    .get();

  if (snapshot.empty) {
    return [];
  } else {
    const data = snapshot.docs.map(doc => {
      const {
        uid,
        phone_number,
        device_uuid,
        device_info,
        is_notifications_accepted,
      } = doc.data() as FirebaseFirestoreTypes.DocumentData;

      return {
        uid,
        device_uuid,
        phone_number,
        device_info,
        is_notifications_accepted,
      };
    });

    return data;
  }
};

export const setUserDataFS = async ({ ...data }: IUserData) => {
  await firestore()
    .collection('users')
    .doc(data.uid)
    .set({ ...data });
};

with that as a base, could you help me to build a test for these scenarios?

[TM-TerryDutton]

So it looks like your /firestore mock isn't returning anything, which is what your code imports from:

jest.mock('@react-native-firebase/firestore', () => {});

It should return a function that itself returns an object with the .collections() etc properties on it. Something like this might work:

jest.mock('@react-native-firebase/firestore', () =>
  jest.fn(() => ({
    collection: jest.fn(() => ({
      where: jest.fn().mockReturnThis(),
      get: jest.fn().mockResolvedValue({
        empty: true,
        docs: [],
      }),
    })),
  }))
);