main.js file for Meteor server

MeteorReactServer.js

import { Meteor } from 'meteor/meteor';
import { collectionName } from '../../imports/collections/collectionName';

Meteor.startup(() => {
  
  // Place to generate data
  // or Check to see if data exists in the collection
  // or See if the collection has any records
  // or ny other logic...
  
   Meteor.publish('publicationName', function([arg]) { // arguments 'arg' is optional
     return collectionName.find({}, { limit: arg });  // find everything, but limit to whatever passed to arg - optional
       });
});

Bardziej skomplikowany publish:

Meteor.publish('publicationName', function() {
    const user = Meteor.users.findOne(this.userId);
    if (!user) { return; }                                                // jeżeli ktoś wchodzi na stronę i jest niezalogowany, nic mu nie pokazuj
    const email = user.emails[0].address;                  // pobierz adres email zalogowanego użytkownika

    return collectionName.find({
      sharedWith: { $elemMatch: { $eq: email }}
    });
  });

Look at the sharedWith property, inside this property this should be an array and inside of this array do an $elemMatch operation, where we want to find an element equal to email.

Możemy mieć zdefiniowanych kilka publications w jednym pliku.