lamassu-server/lib/event-bus.js
2019-11-12 11:20:57 +00:00

29 lines
761 B
JavaScript

// Adapted from https://medium.com/@soffritti.pierfrancesco/create-a-simple-event-bus-in-javascript-8aa0370b3969
const uuid = require('uuid')
const _ = require('lodash/fp')
const subscriptions = {}
function subscribe (eventType, callback) {
const id = uuid.v1()
if (!subscriptions[eventType]) subscriptions[eventType] = {}
subscriptions[eventType][id] = callback
return {
unsubscribe: () => {
delete subscriptions[eventType][id]
if (_.keys(subscriptions[eventType]).length === 0) delete subscriptions[eventType]
}
}
}
function publish (eventType, arg) {
if (!subscriptions[eventType]) return
_.keys(subscriptions[eventType]).forEach(key => subscriptions[eventType][key](arg))
}
module.exports = { subscribe, publish }