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Zero Config PWA Plugin for Next.js

This plugin is powered by workbox and other good stuff.

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👋 Share your awesome PWA project 👉 here

Features

NOTE 1 - next-pwa version 2.0.0+ should only work with next.js 9.1+, and static files should only be served through public directory. This will make things simpler.

NOTE 2 - If you encounter error TypeError: Cannot read property **'javascript' of undefined** during build, please consider upgrade to webpack5 in next.config.js.

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Install

If you are new to next.js or react.js at all, you may want to first checkout learn next.js or next.js document. Then start from a simple example or progressive-web-app example in next.js repository.

yarn add next-pwa

Basic Usage

Step 1: withPWA

Update or create next.config.js with

const withPWA = require('next-pwa')({
  dest: 'public'
})

module.exports = withPWA({
  // next.js config
})

After running next build, this will generate two files in your public: workbox-*.js and sw.js, which will automatically be served statically.

If you are using Next.js version 9 or newer, then skip the options below and move on to Step 2.

If you are using Next.js older than version 9, you'll need to pick an option below before continuing to Step 2.

Option 1: Host Static Files

Copy files to your static file hosting server, so that they are accessible from the following paths: https://yourdomain.com/sw.js and https://yourdomain.com/workbox-*.js.

One example is using Firebase hosting service to host those files statically. You can automate the copy step using scripts in your deployment workflow.

For security reasons, you must host these files directly from your domain. If the content is delivered using a redirect, the browser will refuse to run the service worker.

Option 2: Use Custom Server

When an HTTP request is received, test if those files are requested, then return those static files.

Example server.js

const { createServer } = require('http')
const { join } = require('path')
const { parse } = require('url')
const next = require('next')

const app = next({ dev: process.env.NODE_ENV !== 'production' })
const handle = app.getRequestHandler()

app.prepare().then(() => {
  createServer((req, res) => {
    const parsedUrl = parse(req.url, true)
    const { pathname } = parsedUrl

    if (pathname === '/sw.js' || /^\/(workbox|worker|fallback)-\w+\.js$/.test(pathname)) {
      const filePath = join(__dirname, '.next', pathname)
      app.serveStatic(req, res, filePath)
    } else {
      handle(req, res, parsedUrl)
    }
  }).listen(3000, () => {
    console.log(`> Ready on http://localhost:${3000}`)
  })
})

The following setup has nothing to do with next-pwa plugin, and you probably have already set them up. If not, go ahead and set them up.

Step 2: Add Manifest File (Example)

Create a manifest.json file in your public folder:

{
  "name": "PWA App",
  "short_name": "App",
  "icons": [
    {
      "src": "/icons/android-chrome-192x192.png",
      "sizes": "192x192",
      "type": "image/png",
      "purpose": "any maskable"
    },
    {
      "src": "/icons/android-chrome-384x384.png",
      "sizes": "384x384",
      "type": "image/png"
    },
    {
      "src": "/icons/icon-512x512.png",
      "sizes": "512x512",
      "type": "image/png"
    }
  ],
  "theme_color": "#FFFFFF",
  "background_color": "#FFFFFF",
  "start_url": "/",
  "display": "standalone",
  "orientation": "portrait"
}

Step 3: Add Head Meta (Example)

Add the following into _document.jsx or _app.tsx, in <Head>:

<meta name="application-name" content="PWA App" />
<meta name="apple-mobile-web-app-capable" content="yes" />
<meta name="apple-mobile-web-app-status-bar-style" content="default" />
<meta name="apple-mobile-web-app-title" content="PWA App" />
<meta name="description" content="Best PWA App in the world" />
<meta name="format-detection" content="telephone=no" />
<meta name="mobile-web-app-capable" content="yes" />
<meta name="msapplication-config" content="/icons/browserconfig.xml" />
<meta name="msapplication-TileColor" content="#2B5797" />
<meta name="msapplication-tap-highlight" content="no" />
<meta name="theme-color" content="#000000" />

<link rel="apple-touch-icon" href="/icons/touch-icon-iphone.png" />
<link rel="apple-touch-icon" sizes="152x152" href="/icons/touch-icon-ipad.png" />
<link rel="apple-touch-icon" sizes="180x180" href="/icons/touch-icon-iphone-retina.png" />
<link rel="apple-touch-icon" sizes="167x167" href="/icons/touch-icon-ipad-retina.png" />

<link rel="icon" type="image/png" sizes="32x32" href="/icons/favicon-32x32.png" />
<link rel="icon" type="image/png" sizes="16x16" href="/icons/favicon-16x16.png" />
<link rel="manifest" href="/manifest.json" />
<link rel="mask-icon" href="/icons/safari-pinned-tab.svg" color="#5bbad5" />
<link rel="shortcut icon" href="/favicon.ico" />
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Roboto:300,400,500" />

<meta name="twitter:card" content="summary" />
<meta name="twitter:url" content="https://yourdomain.com" />
<meta name="twitter:title" content="PWA App" />
<meta name="twitter:description" content="Best PWA App in the world" />
<meta name="twitter:image" content="https://yourdomain.com/icons/android-chrome-192x192.png" />
<meta name="twitter:creator" content="@DavidWShadow" />
<meta property="og:type" content="website" />
<meta property="og:title" content="PWA App" />
<meta property="og:description" content="Best PWA App in the world" />
<meta property="og:site_name" content="PWA App" />
<meta property="og:url" content="https://yourdomain.com" />
<meta property="og:image" content="https://yourdomain.com/icons/apple-touch-icon.png" />

<!-- apple splash screen images -->
<!--
<link rel='apple-touch-startup-image' href='/images/apple_splash_2048.png' sizes='2048x2732' />
<link rel='apple-touch-startup-image' href='/images/apple_splash_1668.png' sizes='1668x2224' />
<link rel='apple-touch-startup-image' href='/images/apple_splash_1536.png' sizes='1536x2048' />
<link rel='apple-touch-startup-image' href='/images/apple_splash_1125.png' sizes='1125x2436' />
<link rel='apple-touch-startup-image' href='/images/apple_splash_1242.png' sizes='1242x2208' />
<link rel='apple-touch-startup-image' href='/images/apple_splash_750.png' sizes='750x1334' />
<link rel='apple-touch-startup-image' href='/images/apple_splash_640.png' sizes='640x1136' />
-->

Tip: Put the viewport head meta tag into _app.js rather than in _document.js if you need it.

<meta
  name='viewport'
  content='minimum-scale=1, initial-scale=1, width=device-width, shrink-to-fit=no, user-scalable=no, viewport-fit=cover'
/>

Offline Fallbacks

Offline fallbacks are useful when the fetch failed from both cache and network, a precached resource is served instead of present an error from browser.

To get started simply add a /_offline page such as pages/_offline.js or pages/_offline.jsx or pages/_offline.ts or pages/_offline.tsx. Then you are all set! When the user is offline, all pages which are not cached will fallback to '/_offline'.

Use this example to see it in action

next-pwa helps you precache those resources on the first load, then inject a fallback handler to handlerDidError plugin to all runtimeCaching configs, so that precached resources are served when fetch failed.

You can also setup precacheFallback.fallbackURL in your runtimeCaching config entry to implement similar functionality. The difference is that above method is based on the resource type, this method is based matched url pattern. If this config is set in the runtimeCaching config entry, resource type based fallback will be disabled automatically for this particular url pattern to avoid conflict.

Configuration

There are options you can use to customize the behavior of this plugin by adding pwa object in the next config in next.config.js:

const withPWA = require('next-pwa')({
  dest: 'public'
  // disable: process.env.NODE_ENV === 'development',
  // register: true,
  // scope: '/app',
  // sw: 'service-worker.js',
  //...
})

module.exports = withPWA({
  // next.js config
})

Available Options

Other Options

next-pwa uses workbox-webpack-plugin, other options which could also be put in pwa object can be found ON THE DOCUMENTATION for GenerateSW and InjectManifest. If you specify swSrc, InjectManifest plugin will be used, otherwise GenerateSW will be used to generate service worker.

Runtime Caching

next-pwa uses a default runtime cache.js

There is a great chance you may want to customize your own runtime caching rules. Please feel free to copy the default cache.js file and customize the rules as you like. Don't forget to inject the configurations into your pwa config in next.config.js.

Here is the document on how to write runtime caching configurations, including background sync and broadcast update features and more!

Tips

  1. Common UX pattern to ask user to reload when new service worker is installed
  2. Use a convention like {command: 'doSomething', message: ''} object when postMessage to service worker. So that on the listener, it could do multiple different tasks using if...else....
  3. When you are debugging service worker, constantly clean application cache to reduce some flaky errors.
  4. If you are redirecting the user to another route, please note workbox by default only cache response with 200 HTTP status, if you really want to cache redirected page for the route, you can specify it in runtimeCaching such as options.cacheableResponse.statuses=[200,302].
  5. When debugging issues, you may want to format your generated sw.js file to figure out what's really going on.
  6. Force next-pwa to generate worker box production build by specify the option mode: 'production' in your pwa section of next.config.js. Though next-pwa automatically generate the worker box development build during development (by running next) and worker box production build during production (by running next build and next start). You may still want to force it to production build even during development of your web app for following reason:
    1. Reduce logging noise due to production build doesn't include logging.
    2. Improve performance a bit due to production build is optimized and minified.
  7. If you just want to disable worker box logging while keeping development build during development, simply put self.__WB_DISABLE_DEV_LOGS = true in your worker/index.js (create one if you don't have one).
  8. It is common developers have to use userAgent string to determine if users are using Safari/iOS/MacOS or some other platform, ua-parser-js library is a good friend for that purpose.

Reference

  1. Google Workbox
  2. ServiceWorker, MessageChannel, & postMessage by Nicolás Bevacqua
  3. The Service Worker Lifecycle
  4. 6 Tips to make your iOS PWA feel like a native app
  5. Make Your PWA Available on Google Play Store

Fun PWA Projects

  1. Experience SAMSUNG on an iPhone - must open on an iPhone to start
  2. App Scope - like an app store for PWA
  3. PWA Directory
  4. PWA Builder - Alternative way to build awesome PWA

License

MIT