Everything you need to enable Web Push Notification in your Node.JS web application. Uses the browser's delivery channel to send push notification(Free of cost), which means no extra third-party service (except for the browser's own delivery channel). Works with Progressive Web Apps (PWA).

Before starting the setup, you need to create own own VAPID key pair. This is extremely easy to do. You can go to this site and generate them online. Or you can generate them from Command line using this tool

Once you have your VAPID key pair (Public and Private key), you can use them to setup your web push implementation.

This package contains both the client and server tools packaged in their own module loading format. To install the package run this:

yarn add pushkit

Pushkit works with the Service Worker API. It's journey starts when the service worker gets registered. Below is an example code that sets up pushkit with the service worker registration and sends the Push Registration information (URL and key to send push notification payload) to the server using the fetch API. You can use it like this, or use a different method to preserve the Push Registration object. (Which is Serializable). Once a browser generates this, it can be used to send push notification to that browser.

import {PushKit} from "pushkit/client";
// create an instance
let pkInstance = new PushKit("PUBLIC_VAPID_KEY", true);
// register service worker
navigator.serviceWorker.register("./sw.js").then(swreg=>{
    // start push registration after service worker registration
    pkInstance.handleRegistration(swreg).then(pushreg=>{
        // Once push registration is done
        // Send the registration data to the server
        // You can implement this part in your convenient way
        // The below example uses `fetch` API to do it.
        let regData = JSON.stringify(pushreg);
        fetch("/reg", {
            method  : "POST",
            body    : regData,
            headers : {
                "content-type":"application/json"
            }
        });
    })

The above code creates a PushKit Instance, The constructor takes two arguments, The first argument is required. The second argument is false by default, setting it true will generate console logs.

let _pk = new PushKit("<PUBLIC_VAPID_KEY>", [verbose = false]);

The registration of service worker is not included in the plugin itself. This is to avoid getting in the user's way. Besides it's simple. The method navigator.serviceWorker.register takes the service worker file (more in this later) and returns a promise. This promise is resolved with a ServiceWorkerRegistration object.

pushKitInstance.handleRegistration(ServiceWorkerRegistration)

this also returns a promise that resolves either with a null if the user denies, or push is not supported or there's any error. Or the push registration.

The registration object is different for every user and every browser. You have to send this registration object to the server and store it there for that user. In the example, fetch was used to do it. This registration object will be used to send push notification to that user. See this section

If you are not using a module bundler, or you'd like to use a CDN for the frontend part instead, you can manually add the script tag in your HTML file like this:

<script src="https://unpkg.com/pushkit@3.0.2/client/dist/index.js"></script>

If you chose to include the JavaScript file in your HTML, instead of calling new PushKit() you have to call new pushKit.PushKit(). Every other frontend API are the same.

To set up the server, install the pushkit package on the server as well and then it can be imported like this:

const createSender  = require("pushkit/server");
let sender     = createSender({
    publicKey  : "PUBLIC_VAPID_KEY",
    privateKey : "PRIVATE_VAPID_KEY"
},"your@email.address");

The Email Address is requred for web push API. Once instance of sender is enough for one set of vapid key (one application).

sender.send(pushRegistrationObject, title, [config]);

let config = {
    body: "Street dogs don't want anything more than love and shelter."
}
// Here, the `pushRegistrationObject` is the object sent from the client that was stored on the server.
// Make sure to parse the pushRegistrationObject from JSON string
sender.send(pushRegistrationObject,"Adopt a street dog today!", config);

The config object can be used to customize the behaviour of the push notification. These can be sent from the server as per-message basis or can be set in the service worker binding as default. Settings sent from server will always get precedence over default settings.

A more detailed documentation on the config options are here: https://developer.mozilla.org/en-US/docs/Web/API/ServiceWorkerRegistration/showNotification

The last piece of puzzle is to set up a service worker. Now if you are using a boilerplate/generator there's a chance that you already have a service worker. A service worker is a JavaScript file that gets loaded in the client in such a way, that it can still remain active even after you've left the web application. That's why Service workers can receive push notifications. In the client setup section we used a service worker file called sw.js, the URL should be accessible from the browser and have to be on the same domain (for security reasons).

If you don't have a service worker, create one, if you have one, open it, and import the piece of code required to initiate the service Worker. You can either use it from CDN, or download the worker/binding.js file from the repository and import it.

importScripts("https://unpkg.com/pushkit@3.0.2/worker/binding.js"); 

Then you can attach the pushkit listeners with your service worker like this:

attachPushKit(self, pushConfig, [defaultTitle = "", defaultURL = "", verbose = false]);

Sample Use in service worker:

importScripts("https://unpkg.com/pushkit@3.0.2/worker/binding.js"); 
var pushConfig = {
    icon  : "ICON_URL",
    badge : "BADGE_URL"
}
attachPushKit(self, pushConfig);

The PushConfig object can have any properties from the Configuring Push Behavior section above.If the same properties are also sent from the server, server values will get precedence. You can read the full documentation of the available config options here: https://developer.mozilla.org/en-US/docs/Web/API/ServiceWorkerRegistration/showNotification

If your backend is written in a different language, and you want to use Pushkit in the frontend only. You can definitely do that. Pushkit only knows JSON push data. You have to send JSON string as push data in the following format:

{
    "title"   : "Push Notification Title",
    "url"     : "https://where-to-go",
    "config"  : {
        "body": "Push notification body"
    }
}

This config here can have any value from here, Pushkit will be able to parse this and work without any issues.

One more thing, Make sure your application is served from a secure origin https. otherwise push notification will not work.

This tool is released under the MIT License. Feel free to contribute.

Made with 💙 and JavaScript