sw-precache-list

Precaching that keeps you in control of your service worker.

Want to generate a list of static resources to precache with your service worker?

Want to be able to write your own service worker script?

sw-precache-list may be for you...

Please note, this tool is in progress and probably not suitable for production usage yet.

Example usage

Command line

sw-precache-list 'images/**/*' 'css/*'

NB. If your OS supports globs natively then you could use them directly, e.g. sw-precache-list images/* css/*

As part of your build process

Coming soon...

var swPrecacheList = require('sw-precache-list');

swPrecacheList.write(`${rootDir}/precache-list.js`, ['images/**/*', 'css/*']);

Output

The resulting file (default: precache-list.js) will output the resource list to a global variable called precacheList. You can use it in your service worker script via importScripts. Here is an example:

// service-worker.js

importScripts('precache-list.js');

self.addEventListener('install', function(event) {

  function onInstall () {
    return caches.open('myCacheName')
      .then(function(cache) {
        return cache.addAll( precacheList );
      });
  }

  event.waitUntil(onInstall(event));
});

Or even easier, using sw-toolbox:

importScripts('lib/sw-toolbox.js');
importScripts('precache-list.js');

toolbox.precache(precacheList);

How does this compare to sw-precache?

sw-precache is designed to generate the whole service worker script for you. You cannot manually edit it, because it will get overwritten next time you run it.

sw-precache-list is designed to just generate the precache resource list, which you can use in a service worker that you write yourself.

Still to come

Cache-busting

sw-precache-list is currently very new and simple. It does not yet include cache-busting.

This means that right now you should only use it for static resources that will not be updated (except if you update the filenames).

For more information, see sw-precache's note on cache busting here and Jake Archibald's note here.

We expect to add cache-busting soon, or if you'd like to add it, please submit a PR!

Config

We will also need to add the ability to e.g. strip a directory prefix, to convert local file paths into resource URLs.