publisher-subscriber-pattern

About

• Repository contains javascript implementation of publisher-subscriber pattern
• dist/index.js returns Publisher class

Publisher

• takes arguments: emitterInstance, addEventListener and removeEventListener
• exposes methods: subscribe, unsubscribeAll and eventSubscribersCount
• has property: subscribersCount

emitterInstance argument

• object that will be bound to addEventListener and removeEventListener as this (see Function.prototype.bind)

addEventListener and removeEventListener arguments

• methods exposed by emitterInstance which add and remove event listeners, respectively

subscribe method

• requires two arguments: eventName and eventCallback
• accepts optional argument: subscriberInstance that will be bound to eventCallback as this
• subscribes eventCallback to eventName, so whenever event occurs the eventCallback is called (with subscriberInstance as this, if provided)

unsubscribeAll method

• unsubscribes all eventCallbacks from all eventNames
• runs removeEventListener of emitterInstance fro all eventNames

eventSubscriberCount method

• requires argument: eventName
• returns number of eventCallbacks subscribed to the evenName

subscribersCount method

• returns number of eventCallbacks subscribed to all evenNames

Stack

• typescript
• jasmine, chai, sinon
• babel
• node (EventEmitter)

Description

• I wanted to code library which I will be able to reuse in future projects