Todo library using stated library base

TodoLib.js

import createBase from './StatedLibBase';

export default function createTodoLib() {
  
  const base = createBase({ todos: [], isFetching: false });
  const {updateState, state$} = base;
  
  return {
    get state: {return base.state},
    state$,
    addTodo(title) {
      updateState({ todos: base.state.todos.concat({ title }) });
    },
    async fetchTodos() {
      updateState({ isFetching: true });
      const newTodos = await fetchFromCloud();
      updateState({
        isFetching: false,
        todos: base.state.todos.concat(newTodos),
      });
    },
  };

}