Proposal: `browser.alert.create()`

Why

Since:

The classic alert(), prompt() and confirm() methods are not available in serviceWorkers.
Those methods are synchronous and pause the page
They do not clearly indicate their source of origin
They are not supported in Firefox background pages
Using window.create or tabs.create adds a lot of boilerplate to extensions code are not very suitable for small alerts especially on mobile due to the lack of windows .

Resolves: https://github.com/w3c/webextensions/issues/259

Proposal

alert.create(
options // of type alert.AlertOptions
);

Which returns a promise with the returned value.

alert.AlertOptions has the following options:

type: optional, either one of 'alert', 'confirm', 'prompt'. default: 'alert'
title: optional, title of the alert (addition on top of the classic methods)
message: body text of the dialog
defaultValue: optional, default value of type prompt

To have functionality parity with confirm() and prompt(), type 'confirm' and type 'prompt' have been added. This can be dropped if not considered important.

Example

alert.create({
  type: 'prompt',
  message: 'Enter something',
}).then(function (response) {
  let userHasEntered = response;
});

Potential designs

How this will look for the end user can be different across browsers and operating systems. On desktop for example, one can consider a dialog window coming from the extension icon (if present). On mobile, it can be a dialog in the middle of the screen, which clearly shows the extension icon next to it to know its source of origin.

Security considerations

If an alert is already being displayed, calling i18n.alert.create will reject its returned promise.

If many alerts are opened in a short time-frame, browsers can consider a 'do not show again' checkbox just like the classic window.alert() API does.

w3c / webextensions