polyfill

Ballista polyfill

Author: Matt Giuca <mgiuca@chromium.org>

This partial polyfill lets you try out Ballista right now, with some (serious) limitations, in supported browsers. By design, the API does things that aren't possible in a polyfill, so we can't support everything.

Supported browsers

The polyfill requires a web browser with support for Service Workers and Arrow functions. This includes newer versions of Google Chrome / Chromium and Mozilla Firefox. (Tested on Chrome 46 and Firefox 42.)

Limitations of the polyfill

• No registration of handlers (the web app manifest is not used). Instead, the requester must explicitly nominate the URL of the handler.
• If the requester API (navigator.actions.performAction) is used from a service worker, a foreground page on that domain must be open (but it does not need to remain open to receive updates).
• Not able to send actions to native applications.
• Not possible to use clients.openWindow from the 'action' event handler (when the handler's service worker receives an action). The polyfill will automatically open the handler in a new tab for you.

Usage instructions

1. Add ballista-polyfill.js to your requester or handler JavaScript context (as a <script> in HTML for foreground pages, and using importScripts from service workers).
2. Build your requester or handler using the API as described in the explainer.