"Change" event to subscribe to so extension pages can update each other

[tdriley]

I'm interested in migrating over to this from https://github.com/tshaddix/webext-redux but I need something that lets me subscribe to changes to stored data when they are set from other parts of the extension.

Would this be something that can be added, theoretically?

[fregante]

It's already kind of possible but there's no way to find what changed exactly:

https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/storage/onChanged

chrome.storage.onChanged.addListener(async (changes, area) => {
	if (!changes.options || area !== 'sync') {
		return;
	}

	console.log('the options were updated', await optionsSync.getAll())
});

At a minimum I can export a method that lets you manually parse the zipped changes.options.oldValue string so you can access it and diff it yourself. That would be an easy feature.

Adding a optionsStora.onChange event would be a bit more involved, but I'd accept a PR too, as long as reasonable in size.

[fregante]

Oh actually the decode is already exported:

chrome.storage.onChanged.addListener((changes, area) => {
	if (!changes.options || area !== 'sync') {
		return;
	}

	const old = optionsStorage._decode(changes.options.oldValue);
	const new = optionsStorage._decode(changes.options.newValue);
	// Run your own diffing 

});