communication-bus/src/publisher.js

Publisher subscriber library for communication in JS across components

import Subscribers from "./subscribers";
import Validator from "./validator";
import EventSchemaMap from "./schema";

const publishedEvents = [];

const publish = (eventName, data = {}) => {
  if (!eventName) throw new Error("Event name is required");

  const schema = EventSchemaMap[eventName];
  if (!schema) throw new Error(`${eventName} is not registered`);

  const isValid = Validator.validate(data, schema);
  if (!isValid) throw new Error("Event data failed to match the schema");

  Subscribers.getOrderedSubscribers().map(callback => {
    try {
      callback(eventName, data);
    } catch (e) {}
  });

  publishedEvents.push({ eventName, data });
};

const rePublishEventForSubscriber = (subscriberId, offset = 0) => {
  if (!subscriberId) throw new Error("SubscriberId is required");
  if (offset < 1) throw new Error("Offset value must be greater than 0");
  if (publishedEvents.length < 1) return false;

  let i = publishedEvents.length - offset;
  i = i < 0 ? 0 : i;

  for (; i < publishedEvents.length; i++) {
    Subscribers.getSubscriberById(subscriberId)(publishedEvents[i]);
  }
};

export default {
  publish,
  rePublishEventForSubscriber
};