publisher-subscriber-ts

Publisher subscriber library for javascript.

Setup

1. npm install
2. npm run prepare

Prepare will build this project and create a lib folder which'll contain publisher.min.js for consumption. It'll also create a ES6 version called publisher.es.js and couple of declaration files.

Running test

3. npm run test

This will execute Jest on project.

Usage

• This package has concept of Publisher and Subscriber

• A Publisher communicates with all it's Subscriber through something called Topic

• A Publisher can create any number of Topic and emit event/data to each Topic

• A Subscriber can subscribe/listen to any number of Topic by providing a callback function

• A Subscriber can unsubscribe any Topic at any given time

Example

1. Creating a Topic

// @class Publisher has static helper methods
const  topic1  =  Publisher.createTopic("Topic 1");

2. Subscribing a Topic

// Subscription option takes topic name and optional 'getLastValue' flag which indicates if subscriber should reveice last emitted value from topic
const  subscriptionOption  = {
    topicName: "Topic 1",
    getLastValue: true
};

// @class Publisher has static helper methods
const  subscription1  =  Publisher.subscribeTopic(subscriptionOption, (event) => {
    console.log('Callback function event: ', event);
});

3. Emitting date from topic

const  event  = {
    data: 'Some random data to be broadcasted'
};

// We use object created from "Publisher.createTopic()"
topic1.publish(event);

4. Unsubscribing a Topic

// @class Publisher has static helper methods. Pass subscription object to be unsubscribed.
Publisher.unsubscribeTopic(subscription1);

Documentation

1. @class Publisher

Method	Description
createTopic(topicName: string)	Creates new topic for given topic name
subscribeTopic(option: SubscribeOption, callback: Function): Subscriber	Subscribe to a particular topic by providing option and a callback function
unsubscribeTopic(subscriber: Subscriber)	Unsubscribe any given subscriber

2. @class Subscriber

Method	Description
callBack	Getter for returning callback function
id	Getter for returning subscrber ID
topicName	Getter for returning topic name

3. @class Topic

Method	Description
publish(event: any)	Publish any event for current topic. Once event is published all active subscribers will get a notification in callback function
unsubscribe(subscription: Subscriber)	Method to unsubscribe/remove a listener of this topic
topicName	Getter for returning topic name

4. @interface SubscribeOption

Property	Description
topicName	Required string option to pass name
getLastValue	Optional boolean flag to indicate if last emitted value from topic should be re-emitted for given subscriber only. Default value is false