I did it like this
catalog of the project > npm install vue
or -g ??
!! Probably wrong, but it works.
install vue@2.6.11

@jitendra16 ???
npm run build - start
npm version patch - increment version ( package.json “version”: “0.0.1”)
quasar build -m pwa - build pwa ( process.env.version - get version in project )
cp -R distAdd/* dist/pwa” - copy all files from directory distAdd to dist/pwa after build
UPD: That process.env.version would work
quasar.conf.js
. . build: {
. . . env: { version: JSON.stringify(require("./package.json").version) },
. . .

Can any of this help?
quasar 1.11.2
// server nodejs

const admin = require("firebase-admin");  // npm

var serviceAccount = require("./key_firebase.json"); //  Private Key 
    - To generate a private key file for your service account:
    - In the Firebase console, open Settings > Service Accounts.
    - Click Generate New Private Key, then confirm by clicking Generate Key.
    - Securely store the JSON file containing the key.

admin.initializeApp({
  credential: admin.credential.cert(serviceAccount),
  databaseURL: "https://<<ProjectName>>.firebaseio.com"
});
// -------------------------------------------------------------
var registrationToken ="SfDeDN2Aw5iUBn9UHcx....."  // client ,? ( for test )
var message = {
  data: {
    title: "TitleHello",
    body: "Hello World",
    icon: "/statics/icons/icon-128x128.png",
    image: "/statics/dom_300.png",
    . . . . . . 
   }
  },
  //token: registrationToken  // if token from client
  topic: "allUsers"  // if for topic
};

// Send a message to the device corresponding to the provided
admin
  .messaging()
  .send(message)
  .then(response => {
    // Response is a message ID string.
    console.log("Successfully sent message:", response);
  })
  .catch(error => {
    console.log("Error sending message:", error);
  });

// sample if topic

. . . . (req,res){ 
let idTokens = [req.body.idToken];
 admin
   .messaging()
   .subscribeToTopic(idTokens, "allUsers")  // idTokens  From the client,   allUsers - name topic
        .then(function(response) {
 . . .

workboxPluginMode: “InjectManifest”,

// custom-service-worker,js

importScripts("https://www.gstatic.com/firebasejs/7.14.2/firebase-app.js");
importScripts( "https://www.gstatic.com/firebasejs/7.14.2/firebase-messaging.js");
 // Your web app's Firebase configuration  ->  console firebase  Firebase SDK snippet
  var firebaseConfig = { .. }

firebase.initializeApp(firebaseConfig);
const messaging = firebase.messaging();
messaging.setBackgroundMessageHandler(function(payload) {
  let notifi = payload.data;
  const notificationTitle = notifi.title; //"Background Message Title";
  const notificationOptions = {
    actions: [
      {
        action: "https://google.ru",
        title: "click me"
      }
    ],
    body: notifi.body,
    icon: notifi.icon,
    image: notifi.image,
    requireInteraction: true // Do not clean message
  };
  return self.registration.showNotification(
    notificationTitle,
    notificationOptions
  );
});

. . .

???
self.addEventListener( "notificationclick",  function(event) {
. . .

// register-service-worker.js

import { register } from "register-service-worker";  // help npm ( includes to quasar ?)
. . . 
register(process.env.SERVICE_WORKER_FILE, {
  registrationOptions: { scope: "./" },
  ready(registration) {
 . . . 
firebase.initializeApp(firebaseConfig);
const messaging = firebase.messaging();
  messaging.useServiceWorker(registration); // Your sw (service-worker,js -> custom-service-worker.js)  instead   firebase-messaging-sw.js
. . .
 messaging.onMessage(payload => {
  ... .. .. registration.showNotification(title, options)
})  // no sw, no background
. . . get token
 messaging
        .getToken()
        .then(idToken=> {
          if (idToken) { -> axios to server, for logics to topics
, 
}

quasar/app v2.0.0 released https://forum.quasar-framework.org/topic/6192/quasar-app-v2-0-0-released-major-improvements

• Support for a /public folder which replaces /src/statics. The new folder will allow you to supply static content at the root/app base level, rather than as statics/*.

quasar/app v2.0.0 released https://forum.quasar-framework.org/topic/6192/quasar-app-v2-0-0-released-major-improvements

• Support for a /public folder which replaces /src/statics. The new folder will allow you to supply static content at the root/app base level, rather than as statics/*.

https://vuejs.org/v2/api/#vm-set

@aeiosapp
quasar.conf.json

build:{
   env: {...require("./config_env")}
  ... or
   env: {
        version: require("./package.json").version,
        ...require("./config_env")
      },
 ... or
  env: {...require("./config_env"), 
        ...require("./config_env-2"}

./config_env.js

module.exports={
 title: "no dotenv"
}

@DineshDinux

<q-tree  . . .  . . .  . .>
  <template v-slot:default-header="prop">
    <div class="row items-center text-no-wrap no-wrap">
        {{prop.node.name}}
         <q-tooltip :delay="1500" :offset="[0, 10]" max-width="250px">
            {{ prop.node.id }}  <br />  {{ prop.node.name }}
         </q-tooltip>
     </div>
  </template>
</q-tree>

@jitendra16 ???
npm run build - start
npm version patch - increment version ( package.json “version”: “0.0.1”)
quasar build -m pwa - build pwa ( process.env.version - get version in project )
cp -R distAdd/* dist/pwa” - copy all files from directory distAdd to dist/pwa after build
UPD: That process.env.version would work
quasar.conf.js
. . build: {
. . . env: { version: JSON.stringify(require("./package.json").version) },
. . .

Copy to dist:
package.json
“scripts”: {
“build”: “npm version patch && quasar build -m pwa && cp -R distAdd/* dist/pwa”,

-> messaging.useServiceWorker(registration); registration = any ServiceWorkerRegistration
https://quasar.dev/quasar-cli/developing-pwa/handling-service-worker
… ready(registration){
const messaging = firebase.messaging();
messaging.useServiceWorker(registration);
}

Use custom-service-worker.js instead of firebase-messaging-sw.js

Can any of this help?
quasar 1.11.2
// server nodejs

const admin = require("firebase-admin");  // npm

var serviceAccount = require("./key_firebase.json"); //  Private Key 
    - To generate a private key file for your service account:
    - In the Firebase console, open Settings > Service Accounts.
    - Click Generate New Private Key, then confirm by clicking Generate Key.
    - Securely store the JSON file containing the key.

admin.initializeApp({
  credential: admin.credential.cert(serviceAccount),
  databaseURL: "https://<<ProjectName>>.firebaseio.com"
});
// -------------------------------------------------------------
var registrationToken ="SfDeDN2Aw5iUBn9UHcx....."  // client ,? ( for test )
var message = {
  data: {
    title: "TitleHello",
    body: "Hello World",
    icon: "/statics/icons/icon-128x128.png",
    image: "/statics/dom_300.png",
    . . . . . . 
   }
  },
  //token: registrationToken  // if token from client
  topic: "allUsers"  // if for topic
};

// Send a message to the device corresponding to the provided
admin
  .messaging()
  .send(message)
  .then(response => {
    // Response is a message ID string.
    console.log("Successfully sent message:", response);
  })
  .catch(error => {
    console.log("Error sending message:", error);
  });

// sample if topic

. . . . (req,res){ 
let idTokens = [req.body.idToken];
 admin
   .messaging()
   .subscribeToTopic(idTokens, "allUsers")  // idTokens  From the client,   allUsers - name topic
        .then(function(response) {
 . . .

workboxPluginMode: “InjectManifest”,

// custom-service-worker,js

importScripts("https://www.gstatic.com/firebasejs/7.14.2/firebase-app.js");
importScripts( "https://www.gstatic.com/firebasejs/7.14.2/firebase-messaging.js");
 // Your web app's Firebase configuration  ->  console firebase  Firebase SDK snippet
  var firebaseConfig = { .. }

firebase.initializeApp(firebaseConfig);
const messaging = firebase.messaging();
messaging.setBackgroundMessageHandler(function(payload) {
  let notifi = payload.data;
  const notificationTitle = notifi.title; //"Background Message Title";
  const notificationOptions = {
    actions: [
      {
        action: "https://google.ru",
        title: "click me"
      }
    ],
    body: notifi.body,
    icon: notifi.icon,
    image: notifi.image,
    requireInteraction: true // Do not clean message
  };
  return self.registration.showNotification(
    notificationTitle,
    notificationOptions
  );
});

. . .

???
self.addEventListener( "notificationclick",  function(event) {
. . .

// register-service-worker.js

import { register } from "register-service-worker";  // help npm ( includes to quasar ?)
. . . 
register(process.env.SERVICE_WORKER_FILE, {
  registrationOptions: { scope: "./" },
  ready(registration) {
 . . . 
firebase.initializeApp(firebaseConfig);
const messaging = firebase.messaging();
  messaging.useServiceWorker(registration); // Your sw (service-worker,js -> custom-service-worker.js)  instead   firebase-messaging-sw.js
. . .
 messaging.onMessage(payload => {
  ... .. .. registration.showNotification(title, options)
})  // no sw, no background
. . . get token
 messaging
        .getToken()
        .then(idToken=> {
          if (idToken) { -> axios to server, for logics to topics
, 
}

@rstoenescu Hooray! Thanks.

The icon file needs to be square. That’s all.

and they don’t need to have a fixed width + height.

I thought, this means that the square is not necessary …
Well, so be it. thanks.