Configuring PWA

We’ll be using Quasar CLI to develop and build a PWA. The difference between building a SPA, Mobile App, Electron App, PWA or SSR is simply determined by the “mode” parameter in “quasar dev” and “quasar build” commands.

Installation

In order to build a PWA, we first need to add the PWA mode to our Quasar project:

$ quasar mode add pwa

If you want to jump right in and start developing, you can skip the “quasar mode” command and issue:

$ quasar dev -m pwa

This will add PWA mode automatically, if it is missing.

Service Worker

Adding PWA mode to a Quasar project means a new folder will be created: /src-pwa, which contains PWA specific files:

.
└── src-pwa/
    ├── register-service-worker.js  # App-code *managing* service worker
    └── custom-service-worker.js    # Optional custom service worker
                                    # file (InjectManifest mode oNLY)

You can freely edit these files. Notice a few things:

  1. register-service-worker.js is automatically imported into your app (like any other /src file). It registers the service worker (created by Workbox or your custom one, depending on workbox plugin mode – quasar.conf.js > pwa > workboxPluginMode) and you can listen for Service Worker’s events. You can use ES6 code.
  2. custom-service-worker.js will be your service worker file ONLY if workbox plugin mode is set to “InjectManifest” (quasar.conf.js > pwa > workboxPluginMode: ‘InjectManifest’). Otherwise, Workbox will create a service-worker file for you.
  3. It makes sense to run Lighthouse tests on production builds only.

TIP

Read more on register-service-worker.js and how to interact with the Service Worker on Handling Service Worker documentation page.

Quasar.conf.js

This is the place where you can configure Workbox behavior and also tweak your manifest.json.

pwa: {
  // workboxPluginMode: 'InjectManifest',
  // workboxOptions: {},
  manifest: {
    // ...
  },

  // variables used to inject specific PWA
  // meta tags (below are default values)
  metaVariables: {
    appleMobileWebAppCapable: 'yes',
    appleMobileWebAppStatusBarStyle: 'default',
    appleTouchIcon120: 'statics/icons/apple-icon-120x120.png',
    appleTouchIcon180: 'statics/icons/apple-icon-180x180.png',
    appleTouchIcon152: 'statics/icons/apple-icon-152x152.png',
    appleTouchIcon167: 'statics/icons/apple-icon-167x167.png',
    appleSafariPinnedTab: 'statics/icons/safari-pinned-tab.svg',
    msapplicationTileImage: 'statics/icons/ms-icon-144x144.png',
    msapplicationTileColor: '#000000'
  }
}

More information: Workbox Webpack Plugin, Workbox.

The metaVariables Object is used by Quasar itself only (has no meaning for Workbox) to inject specific value attributes to some PWA meta tags into the rendered HTML page. Example: <meta name="apple-mobile-web-app-status-bar-style"> will have value attribute assigned to the content of metaVariables.appleMobileWebAppStatusBarStyle.

Picking Workbox mode

There are two Workbox operating modes: GenerateSW (default) and InjectManifest. The first one generates a service worker automatically, based on quasar.conf.js > pwa > workboxOptions (if any), while the second mode allows you to write your own service worker file.

Setting the mode that you want to use is done through quasar.conf.js:

// quasar.conf.js
pwa: {
  // workboxPluginMode: 'InjectManifest',
  // workboxOptions: { ... }
}

WARNING

Make sure that your workboxOptions match the Workbox mode that you have picked, otherwise the workbox webpack plugin might halt your app from compiling.

GenerateSW

When to use GenerateSW:

  • You want to precache files.
  • You have simple runtime configuration needs (e.g. the configuration allows you to define routes and strategies).

When NOT to use GenerateSW:

  • You want to use other Service Worker features (i.e. Web Push).
  • You want to import additional scripts or add additional logic.

TIP

Please check the available workboxOptions for this mode on Workbox website.

InjectManifest

When to use InjectManifest:

  • You want more control over your service worker.
  • You want to precache files.
  • You have more complex needs in terms of routing.
  • You would like to use your service worker with other APIs (e.g. Web Push).

When NOT to use InjectManifest:

  • You want the easiest path to adding a service worker to your site.

TIPS

  • If you want to use this mode, you will have to write the service worker (/src-pwa/custom-service-worker.js) file by yourself.
  • Please check the available workboxOptions for this mode on Workbox website.

Configuring Manifest File

The Manifest file is generated by Quasar CLI with a default configuration for it. You can however tweak this configuration from /quasar.conf.js.

// quasar.conf.js
pwa: {
  // workboxPluginMode: 'InjectManifest',
  // workboxOptions: {},
  manifest: {
    name: 'Quasar Play',
    short_name: 'Quasar-Play',
    description: 'Quasar Framework Showcase',
    icons: [
      {
        'src': 'statics/icons/icon-128x128.png',
        'sizes': '128x128',
        'type': 'image/png'
      },
      {
        'src': 'statics/icons/icon-192x192.png',
        'sizes': '192x192',
        'type': 'image/png'
      },
      {
        'src': 'statics/icons/icon-256x256.png',
        'sizes': '256x256',
        'type': 'image/png'
      },
      {
        'src': 'statics/icons/icon-384x384.png',
        'sizes': '384x384',
        'type': 'image/png'
      },
      {
        'src': 'statics/icons/icon-512x512.png',
        'sizes': '512x512',
        'type': 'image/png'
      }
    ],
    display: 'standalone',
    orientation: 'portrait',
    background_color: '#ffffff',
    theme_color: '#027be3'
  }
}

Please read about the manifest config before diving in.

WARNING

Note that you don’t need to edit your index.html file (generated from /src/index.template.html) to link to the manifest file. Quasar CLI takes care of embedding the right things for you.

PWA Checklist

More info: PWA Checklist

WARNING

Do not run Lighthouse on your development build because at this stage the code is intentionally not optimized and contains embedded source maps (among many other things). See the Testing and Auditing section of these docs for more information.

Reload & Update Workbox

For those who don’t want to manually reload the page when the service worker is updated and are using the default GenerateSW workbox mode, you can make it active at once. Update the workboxOptions config in quasar.conf.js as follows:

// quasar.conf.js
pwa: {
  workboxOptions: {
    skipWaiting: true,
    clientsClaim: true
  }
}

Source