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Vue-Socket.io-Extended

Socket.io bindings for Vue.js 2 and Vuex (inspired by Vue-Socket.io)

⚠️ The alpha version of v5 (with Vue 3 support) has been released. Your feedback would be appreciated here

🍒 Features

• Lightweight and dependency free - only 2kb min gzip
• Reactive properties $socket.connected and $socket.disconnected
• Listening and emitting socket.io events inside components
• Auto-dispatches actions and mutations in multiple namespaced Vuex modules on socket.io events
• Good TypeScript support (decorator and typing)
• Can be used with any version of socket.io-client
• Custom options - tweak the library to better fit your project needs
• etc...

✔️ Browser Support

38+ ✔️	13+ ✔️	8+ ✔️	25+ ✔️	12+ ✔️	11+ ✔️

We support only browsers with global usage statistics greater than 1% and last 2 version of each browser (but not dead browsers). Library may work in older browser as well, but we don't guarantee that. You may need addition polyfills to make it work.

🌱 Motivation

I was using Vue-Socket.io for few months. I've liked the idea, but the more I used it the more I faced with bugs, outdated documentation, lack of support, absence of tests, and a huge amount of issues 😞. That slowed down development of the product I was working on. So I ended up with a decision to create my own fork with all the desirable stuff (features/fixes/tests/support/CI checks etc). That's how vue-socket.io-extended was born.

If you'd like to help - create an issue or PR. I will be glad to see any contribution. Let's make the world a better place ❤️

❕ Prerequisites

You must have a running Socket.IO server before starting any Vue/Socket.IO project! Instructions on how to build a Node/Socket.IO server are found here.

❕ Software Requirements

• Vue.js >=2.X
• Socket.io-client >=2.X
• Vuex >=2.X (optional)

💿 Installation

npm install vue-socket.io-extended socket.io-client

🏁 Initialization

ES2015 (Webpack/Rollup/Browserify/Parcel/etc)

import VueSocketIOExt from 'vue-socket.io-extended';
import { io } from 'socket.io-client';

const socket = io('http://socketserver.com:1923');

Vue.use(VueSocketIOExt, socket);

Note: you have to pass instance of socket.io-client as second argument to prevent library duplication. Read more here.

UMD (Browser)

<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/socket.io-client/dist/socket.io.slim.js"></script>
<script src="https://cdn.jsdelivr.net/npm/vue-socket.io-extended"></script>
<script>
  var socket = io('http://socketserver.com:1923');
  Vue.use(VueSocketIOExt, socket);
</script>

🚀 Usage

On Vue.js component

Define your listeners under sockets section, and they will listen corresponding socket.io events automatically.

new Vue({
  sockets: {
    connect() {
      console.log('socket connected')
    },
    customEmit(val) {
      console.log('this method was fired by the socket server. eg: io.emit("customEmit", data)')
    }
  },
  methods: {
    clickButton(val) {
      // this.$socket.client is `socket.io-client` instance
      this.$socket.client.emit('emit_method', val);
    }
  }
})

Note: Don't use arrow functions for methods or listeners if you are going to emit socket.io events inside. You will end up with using incorrect this. More info about this here

Dynamic socket event listeners (changed in v4)

There is a way to create listeners dynamically, in case you need to start listening only on some condition.

// creating event listener
this.$socket.$subscribe('event_name', payload => {
  console.log(payload)
});

// removing existing listener
this.$socket.$unsubscribe('event_name');

As an alternative, feel free to attach events directly to socket.io client, but keep in mind that you'd need to pass the same function to .off(event_name, fn) that you passed to .on(event_name, fn) in order to unsubscribe properly. Otherwise, it won't work as you expect.

export default {
  methods: {
    onEventName(params) {
      console.log('`eventName` has fired with:', params)
    },
  },
  mounted() {
    // subscribe
    this.$socket.client.on('eventName', this.onEventName) // <-- this.onEventName here
  },
  beforeDestroy() {
    // unsubscribe
    this.$socket.client.off('eventName', this.onEventName) // <-- this.onEventName here
  },
}

Important: Every dynamic subscription should have appropriate unsubscription. Or else, you'd experience an event firing multiple times. Moreover, unsubscribed leftovers might cause memory leaks.

Reactive properties (new in v4)

$socket.connected and $socket.diconnected are reactive. That means you can use them in expressions

<template>
  <div>
    <span>{{ $socket.connected ? 'Connected' : 'Disconnected' }}</span>
  </div>
</template>

Or conditions

<template>
  <span
    class="notification"
    v-if="$socket.disconnected"
  >
    You are disconnected
  </span>
</template>

Or computed properties, methods and hooks. Treat them as computed properties that are available in all components

🌲 Vuex Store Integration

Setup

To set up Vuex integration just pass the store as the third argument. In a Vue CLI project, you might do this in the src/main.js file. Example:

import VueSocketIOExt from 'vue-socket.io-extended';
import { io } from 'socket.io-client';
import store from './store'

const socket = io('http://socketserver.com:1923');

Vue.use(VueSocketIOExt, socket, { store });

Receiving Events

Mutations and actions will be dispatched or committed automatically in the Vuex store when a socket event arrives. A mutation or action must follow the naming convention below to recognize and handle a socket event.

• A mutation should start with SOCKET_ prefix and continue with an uppercase version of the event
• An action should start with socket_ prefix and continue with camelcase version of the event

Server Event	Mutation	Action
chat message	SOCKET_CHAT MESSAGE	socket_chatMessage
chat_message	SOCKET_CHAT_MESSAGE	socket_chatMessage
chatMessage	SOCKET_CHATMESSAGE	socket_chatMessage
CHAT_MESSAGE	SOCKET_CHAT_MESSAGE	socket_chatMessage

Check the Configuration section if you'd like to use a custom transformation.

Check the Migration from VueSocketIO section if you want to keep actions names in UPPER_CASE.

// In this example we have a socket.io server that sends message ID when it arrives
// so to get entire body of the message we need to make AJAX call the server
import Vue from 'vue'
import Vuex from 'vuex'

// `MessagesAPI.downloadMessageById` is an async function (goes to backend through REST Api and fetches all message data)
import MessagesAPI from './api/message'

Vue.use(Vuex);

export default new Vuex.Store({
  state: {
    // we store messages as a dictionary for easier access and interaction
    // @see https://hackernoon.com/shape-your-redux-store-like-your-database-98faa4754fd5
    messages: {},
    messagesOrder: []
  },
  mutations: {
    NEW_MESSAGE(state, message) {
      state.messages[message.id] = message;
      state.messagesOrder.push(message.id);
    }
  },
  actions: {
    socket_userMessage ({ dispatch, commit }, messageId) { // <-- this action is triggered when `user_message` is emmited on the server
      return MessagesAPI.downloadMessageById(messageId).then((message) => {
       commit('NEW_MESSAGE', message);
      })
    }
  }
})

Emitting Events

Events can be sent to the Socket.IO server by calling this._vm.$socket.client.emit from a Vuex mutation or action. Mutation or action names are not subject to the same naming requirements as above. More then one argument can be included. All serializable data structures are supported, including Buffer.

  actions: {
    emitSocketEvent(data) {
      this._vm.$socket.client.emit('eventName', data);
      this._vm.$socket.client.emit('with-binary', 1, '2', { 3: '4', 5: new Buffer(6) });
    }
  }

Namespaced Vuex Modules

Namespaced modules are supported out-of-the-box. Any appropriately-named mutation or action should work regardless of whether it's in a module or in the main Vuex store.

import Vue from 'vue'
import Vuex from 'vuex'

Vue.use(Vuex);

const messages = {
  state: {
    messages: []
  },
  mutations: {
    SOCKET_CHAT_MESSAGE(state, message) {
      state.messages.push(message);
    }
  },
  actions: {
    socket_chatMessage() {
      console.log('this action will be called');
    }
  },
};

const notifications = {
  state: {
    notifications: []
  },
  mutations: {
    SOCKET_CHAT_MESSAGE(state, message) {
      state.notifications.push({ type: 'message', payload: message });
    }
  },
};

export default new Vuex.Store({
  modules: {
    messages,
    notifications,
  }
})

The above code will:

• Commit the SOCKET_CHAT_MESSAGE mutation in the messages module
• Commit the SOCKET_CHAT_MESSAGE mutation in the notification module
• Dispatch the socket_chatMessage action in the messages module

🎍 ECMAScript / TypeScript decorator (added in v4)

Required: ECMAScript stage 1 decorators. If you use Babel, babel-plugin-transform-decorators-legacy is needed. If you use TypeScript, enable --experimentalDecorators flag.

It does not support the stage 2 decorators yet since mainstream transpilers still transpile to the old decorators.

We provide @Socket() decorator for users of class-style Vue components. By default, @Socket() decorator listens the same event as decorated method name but you can use custom name by passing a string inside decorator e.g. @Socket('custom_event').

Check the example below:

<!-- App.vue -->
<script>
import Vue from 'vue'
import Component from 'vue-class-component'
import { Socket } from 'vue-socket.io-extended'

@Component({})
export default class App extends Vue {
  @Socket() // --> listens to the event by method name, e.g. `connect`
  connect () {
    console.log('connection established');
  }

  @Socket('tweet')  // --> listens to the event with given name, e.g. `tweet`
  onTweet (tweetInfo) {
    // do something with `tweetInfo`
  }
}
</script>

🚵 Usage with Nuxt.js

The key point here is to disable SSR for the plugin as it will crash otherwise. It's a well-know issue and we are going to fix it. Thanks @ll931217 for investigation.

1. Create plugin:

// ~/plugins/socket.io.js
import Vue from 'vue';
import { io } from 'socket.io-client';
import VueSocketIOExt from 'vue-socket.io-extended';

const socket = io('http://localhost:3000');

export default ({ store }) => {
  Vue.use(VueSocketIOExt, socket, { store });
}

2. Then register it:

// nuxt.config.js
module.exports = {
  //...,
  plugins: [
    //...,
    {
      src: '~/plugins/socket.io.js',
      ssr: false,                    // <-- this line is required
    },
  ]
}

🚵 Usage with Quasar Framework

Register vue-socket.io-extended with a boot file and disable server side rendering

1. Create bootfile:

// ~/boot/socket.io.js
import { io } from 'socket.io-client';
import VueSocketIOExt from 'vue-socket.io-extended';

const socket = io('http://localhost:3000');

export default async ({ store, Vue }) => {
  Vue.use(VueSocketIOExt, socket, { store })
}

2. Then register it:

// quasar.conf.js
module.exports = function (ctx) {
  return {
    //...,
    boot: [
      //...,
      {
        path: 'socket.io',
        server: false,
      },
    ]
  }
};

⚙️ Configuration

In addition to store instance, vue-socket.io-extended accepts other options. Here they are:

Option	Type	Default	Description
store	Object	undefined	Vuex store instance, enables vuex integration
actionPrefix	String	'socket_'	Prepend to event name while converting event to action. Empty string disables prefixing
mutationPrefix	String	'SOCKET_'	Prepend to event name while converting event to mutation. Empty string disables prefixing
eventToMutationTransformer	Function string => string	uppercase function	Determines how event name converted to mutation
eventToActionTransformer	Function string => string	camelcase function	Determines how event name converted to action
eventMapping	Function socket => string		Map your event from socket event data

FYI: You can always access default plugin options if you need it (e.g. re-use default eventToActionTransformer function):

import VueSocketIOExt from 'vue-socket.io-extended';
VueSocketIOExt.defaults // -> { actionPrefix: '...', mutationPrefix: '...', ... }

ℹ️ Migration from VueSocketIO

For everyone who has migrated from old package VueSocketIO to this new one on existing project. You need to re-define 2 parameters, in order to use existing store actions without changes (e.g. SOCKET_EVENT_NAME).

import VueSocketIO from 'vue-socket.io-extended';
import { io } from 'socket.io-client';

const ioInstance = io('https://hostname/path', {
  reconnection: true,
  reconnectionDelay: 500,
  maxReconnectionAttempts: Infinity
});

Vue.use(VueSocketIO, ioInstance, {
  store, // vuex store instance
  actionPrefix: 'SOCKET_', // (1) keep prefix in uppercase
  eventToActionTransformer: (actionName) => actionName // (2) cancel camelcasing
});

❓ FAQ

• How to prevent connection until authed?

• How to receive/emit event from server to the particular user? (check also this)

• How access this.$socket from Vuex actions?

• My mutation is triggered two times?

• Mutations and actions are not fired while using Quasar

⚓ Semantic Versioning Policy

This plugin follows semantic versioning.

📰 Changelog

We're using GitHub Releases.

🍻 Contribution

We're more than happy to see potential contributions, so don't hesitate. If you have any suggestions, ideas or problems feel free to add new issue, but first please make sure your question does not repeat previous ones.

🔒 License

See the LICENSE file for license rights and limitations (MIT).