app.js

wire(TodoList)

wire.js

function wire(type) {
  const WrappedComponent = type;

  class FinalComponent extends WrappedComponent {
    componentDidMount() {
      // Subscribe
    }

    componentWillUnmount() {
      // Unsubscribe
    }
  }

  // Store a reference to the connected component so we can create an element of it instead of the
  // original type in createElement().
  WrappedComponent[COMPONENT] = FinalComponent;
}