Routing

In this example, a set of tabs are rendered to the screen, with the currently active tab stored in React state.

Aperture

Two sources are observed in this example:

• The setActiveTab callback function.

• The window.popstate event.

In addition, a single event is fired when the aperture initiates, which sets the initial state to initialProps.activeTab.

All three are simply mapped to objects with the desired structure, and merged into a single stream.

Handler

If the effect's type is NAVIGATION, the handler calculates the new browser url, and pushes it to window.history.

If the effect's type is STATE, it calls setState with the new state.

Result

The end result is a set of tabs whose state is pushed to the browser url as a side-effect.