wp-calypso/apps/notifications/README.md

Notifications

The notifications panel (also known as "masterbar notifications" and "the bell notifications") is a cross-environment app that runs directly inside of Calypso and in an iframe on WordPress.com sites which aren't Calypso.

This module is where the code for the notifications panel lives. Calypso views are imported as normal node imports while the iframe version is served from https://wordpress.com/widgets/notifications/ or from the legacy URL https://widgets.wp.com/notifications/.

This code is developed in the calypso monorepo at https://github.com/Automattic/wp-calypso/tree/trunk/apps/notifications.

Building and developing

Most work on the notifications panel should happen in Calypso the same way other Calypso changes are developed. That is, you can work in these files and rely on the normal Calypso dev server. However things are often different inside the iframe in unexpected ways and so we need to verify that any changes apply properly in both environments.

TeamCity generates notifications panel build artifacts on every commit that it processes. You can find the last one in the PR checks by searching for Notifications (WPCom Plugins) then clicking the artifacts tab (requires access to the A8C TeamCity instance).

Alternatively you can manually build the app with yarn and pass --sync to sync to your sandbox automatically (requires your to configure an alias called wpcom-sandbox in ~/.ssh/config):

1. yarn dev --sync to sync a dev build to your sandbox;
2. yarn build --sync to sync a production build to your sandbox.

You will also need to sandbox the widgets.wp.com domain.

# Builds files and places them in `apps/notifications/dist`
cd apps/notifications
yarn build

You will need to follow the directions in the Field Guide to deploy these artifacts.

iframe communication

When running in an iframe communication with the parent frame occurs through a postMessage() exchange.

Messages we handle from the notifications iframe have the form:

const obj = {
    type: 'notesIframeMessage',
    action: action,
    //... other properties depending on action ...
};

• togglePanel: This is a message from the client that the panel open state should be toggled. For example, the user may have pressed the ESC key, which means we should close the panel.

• iFrameReady: The client sends this message when it's code has loaded and it is ready to begin polling for notifications.

• renderAllSeen: A message to indicate that the user has seen all notifications (so we can clear the new notifications indicator).

• widescreen: The client is requesting that it's frame width be changed. We use this to set the appropriate classes so the notifications frame is rendered wider when the user clicks into the detail view of a note or narrower when they close the detail view. When receiving this action, there will be a boolean property widescreen indicating if widescreen mode should be on or not.

• render: Client sends this when the number of new notes changes. The property num_new will indicate the number of new notes available (possibly 0). The type of the latest note will also be available as a string in latest_type.