Firebase - Filtering data from two arrays - node.js

Question

Currently started learning firebase . I want to compare data from two tables. There is a table 'subscribers' and 'clubMembers'. 'clubMembers' contains the full list of users whereas the 'subscribers' contains the list only those user who have subscribed for the event.
I want to compare emails from both table and extract the ones those are not in 'subscribers' table. So to be make more clear if 'clubMember' have 10 emails, and 'subscribers' have 5 emails, so I want the 5 remaining subscriber email who doesn't have subscribed.
here is the code
db.ref('subscribers/' + today).orderByChild("email").once('value').then(snap => {
db.ref('clubMembers').orderByChild("email").once('value') .then(snapshot => {
const finalNames = [];
const allSubscribers = snap.val();
const allMembers = snapshot.val();
for (const user in allMembers) {
const userObject = allMembers[user];
for(const subUser in allSubscribers){
const subUserObject = allSubscribers[subUser];
if (userObject.email !== subUserObject.email) {
finalNames.push(userObject.email);
}
}
}
the finalNames variable displays the full list of emails, not the filtered ones.

Answer 1

this code get to toy diffrence of array after this code and get data is ok from firebase :
db.ref('subscribers/' + today).orderByChild("email").once('value').then(snap => {
db.ref('clubMembers').orderByChild("email").once('value') .then(snapshot => {
const finalNames = [];
const allSubscribers = snap.val();
const allMembers = snapshot.val();
var res = allMembers.filter(item1 =>
!allSubscribers.some(item2 => (item2.email === item1.emial)))
console.log(res);
var allMembers = [
{ id: 0, email: 'john#a.com' },
{ id: 1, email: 'mary#a.com' },
{ id: 2, email: 'pablo#a.com' },
{ id: 3, email: 'escobar#a.com' }
];
var allSubscribers = [
{ id: 0, email: 'john#a.com' },
{ id: 1, email: 'mary#a.com' }
];
var res = allMembers.filter(item1 =>
!allSubscribers.some(item2 => (item2.email === item1.email)))
console.log(res);