vue-easy-subscription

Quick and modular subscriptions for vue!

Installation

npm i vue-easy-subscription
// NOTE: This library requires Vue and Vuex as peer dependencies!

Initialization

There are 2 main ways to use library:

A) As a Vue Plugin

In this scenario, a Vuex store will be created for you by default! Use option B if you wish to integrate it into an already existing Vuex store.

You can initialize the plugin in one of the following ways:

1. Initialize with firestore. The subscription function for firestore is already in the lib:

import vueEasySub from "vue-easy-subscription"
import Vue from "vue"
import Firebase from "firebase"

Firebase.initializeApp({ ... your appConfig })

Vue.use(vueEasySub, { firestore: Firebase.firestore() })

2. Initialize with firebase realtime database. The subscription function for firebase realtime database is already in the lib:

import vueEasySub from "vue-easy-subscription"
import Vue from "vue"
import Firebase from "firebase"

Firebase.initializeApp({ ... your appConfig })

Vue.use(vueEasySub, { firebaseRealtime: Firebase.database() })

3. Initialize with your own subscription function:

import vueEasySub from "vue-easy-subscription"
Vue from "vue"
	
Vue.use(vueEasySub, { sub: yourSubFn(path, updateValueFn) })

/*
	1) yourSubFn must return a function that will unsubscribe from path. The function can be 
	async if you wish.
	2) yourSubFn must call the updateValueFn whenever the value at path is updated.

	---------------------
	Simple example subFn:
	---------------------
	const subFn = (path, updateValue) => {
		const updater = e => updateValue(e);
		window.addEventListener("scroll", updater);
		return () => window.removeEventListener("scroll", updater)
	}
*/

B) As Vuex store module

Use this method if you wish to integrate into an already existing Vuex Store. It is very similar to using method A.

import Vue from "vue"
import Vuex from "vuex"
import VueEasySub from "vue-easy-subscription"

const easySubModules = VueEasySub.getVuexStoreModules(Vue, { sub: yourSubFn(path, updateValueFn) })
const store = new Vuex.Store({
	modules: {
		...easySubModules,
		yourStoreModuleA,
		yourStoreModuleB,
	}
})

Usage

Usage of this lib is very simple and powerful.

To establish a subscription, declare a $subs object in your data()

// inside your vue component
{
	data() {
		return {
			$subs: {
				pet: `pets/1`	// subFn will be called with path = `pets/1`
			}
		}
	},
	computed: {
		pet() {
			// a pet entry will become available in $subData when the subscription
			// returns a value.
			return this.$subData.pet
		}
	}
}

Once this component is destroyed and if there are no other subscribers to pets/1, the library will automatically unsubscribe from pets/1

Establishing subscription using computed property.

{
	props: ['petId'],	// assume we pass in 4
	computed: {
		$subs() {
			return {
				pet: 'pets/${this.petId}'	 // subFn will be called with path = `pets/4`
			}
		},
		pet() {
			// a pet entry will become available in $subData when the subscription
			// returns a value.
			return this.$subData.pet
		}
	}
}

Interdependent subscriptions!

{
	props: ['petId'],	// assume we pass in 4
	computed: {
		$subs() {
			const subs = {
				pet: 'pets/${this.petId}'	 // subFn will be called with path = `pets/4`
			}
			
			if (this.pet) {	// we retrieved this from our subscription!!
				subs.owner = `owners/${this.pet.owner}`
			}

			return subs
		},
		pet() {  return this.$subData.pet },
		owner() { return this.$subData.owner }
	}
}

non-string subscriptions (firestore example)

This example illustrates that the paths dont need to simple strings. As long as they are JSON serialiazible, any path is ok! The builtin firestore subscription function gives support for OR queries!! Firestore, by itself does not have that.

// In the example below, the where query would read as:
// (ownerId === this.ownerId) AND (type === 'DOG' OR type === 'CAT')
{
	props: ['ownerId'],
	computed: {
		$subs() {
			return {
			    pets: {
			        collection: "pet",
			        where: [
                        ["ownerId", "==", this.ownerId],
                        { or: [['type', '==', 'dog'], ['type', '==', 'cat']] }
                    ]
			    }
			}
		},
		// This will contain all the pets whose owner is what is passed into
		// the ownerId prop.
		pets() {  return this.$subData.pets },
	}
}

Using multiple instances

The library comes equipped with being able to handle multiple subscription methods!

Vue.use(VueEasySub, [
	{ firestore:  Firebase.firestore(), name:  'firestore' },
	{ firebaseRealtime:  Firebase.database(), name:  'firebase' },
	{ sub: yourSubFn, name: 'yours' }
])

/* 
subscriptions to firestore will be made using the $firestore_subs property
subscriptions to firebase will be made using the $firebase_subs property
subscriptions to yours will be made using the the $yours_subs property

the results of firestore subscriptions will be available at $firestore_subData
the results of firestore subscriptions will be available at $firebase_subData
the results of firestore subscriptions will be available at $yours_subData
*/

Unsubscribing

As mentioned earlier, the lib will automatically unsubscribe when instances pointing to a subscription are destroyed. You don't have to manually call unsubscribe on anything!