in todo/data/database.js [115:126]
export function removeTodo(id: string) {
const todoIdsForUser = getTodoIdsForUser(USER_ID);
// Remove from the users list
todoIdsByUser.set(
USER_ID,
todoIdsForUser.filter((todoId: string): boolean => todoId !== id),
);
// And also from the total list of Todos
todosById.delete(id);
}