Panel • TodoMVC
Panel makes Web Components suitable for constructing full web UIs, not just low-level building blocks. It does so by providing an easy-to-use state management and rendering layer built on Virtual DOM (the basis of the core rendering technology of React). Through use of the Snabbdom Virtual DOM library and first-class support for multiple templating formats, Panel offers simple yet powerful APIs for rendering, animation, styling, and DOM lifecycle.
The main architectural decisions of this TodoMVC implementation center around how to decompose the UI effectively into a component hierarchy. The approach taken here avoids breaking out components purely for the sake of organization - e.g., the UI header is inlined in the main app component rather than a separate <todo-header>, because there's no functional benefit - but instead simply divides the app into the main UI (<todo-app>) and the individual items (<todo-item>). Individual <todo-item>s share a single central state store with the main app, making state updates seamless and easy across the app. As TodoMVC is a pretty simple app with a tiny state structure (list of todos, current view, todo currently being edited), the example doesn't integrate Redux or any other dedicated state management solution; straightforward update() calls to change the state object and re-render are sufficient for this case.
The title field in the state store is unnecessary and has been included just for purposes of demonstration (e.g., open dev tools and run document.querySelector('todo-app').update({title: 'Hi world!'}) to change the UI title from "todos").
Created by Ted Dumitrescu