[Redux] Redux: Extracting Container Components -- AddTodo

Code to be refactored:

const AddTodo = ({
  onAddClick
}) => {
  let input;

  return (
    <div>
      <input ref={node => {
        input = node;
      }} />
      <button onClick={() => {
        onAddClick(input.value);
        input.value = '';
      }}>
        Add Todo
      </button>
    </div>
  );
}

Finally, in the previous lesson, I made app ToDo a presentational component, but I'm going to backtrack on this now. I will copy-paste the dispatch call back in line into the onClick handler inside the component because there isn't really a lot of presentation or behavior here.

It's easier to keep them together until we figure out how to split the presentation. For example, if in the future, we're going to have something like a form component, we may split it, but for now we'll keep them together.

const AddTodo = ({
  onAddClick
}) => {
  let input;

  return (
    <div>
      <input ref={node => {
        input = node;
      }} />
      <button onClick={() => {
        store.dispatch({
          type: 'ADD_TODO',
          id: nextTodoId++,
          text: input.value
        });
        input.value = '';
      }}>
        Add Todo
      </button>
    </div>
  );
};

---------------------------

Code:

const todo = (state, action) => {
  switch (action.type) {
    case 'ADD_TODO':
      return {
        id: action.id,
        text: action.text,
        completed: false
      };
    case 'TOGGLE_TODO':
      if (state.id !== action.id) {
        return state;
      }

      return {
        ...state,
        completed: !state.completed
      };
    default:
      return state;
  }
};

const todos = (state = [], action) => {
  switch (action.type) {
    case 'ADD_TODO':
      return [
        ...state,
        todo(undefined, action)
      ];
    case 'TOGGLE_TODO':
      return state.map(t =>
        todo(t, action)
      );
    default:
      return state;
  }
};

const visibilityFilter = (
  state = 'SHOW_ALL',
  action
) => {
  switch (action.type) {
    case 'SET_VISIBILITY_FILTER':
      return action.filter;
    default:
      return state;
  }
};

const { combineReducers } = Redux;
const todoApp = combineReducers({
  todos,
  visibilityFilter
});

const { createStore } = Redux;
const store = createStore(todoApp);

const { Component } = React;

const Link = ({
  active,
  children,
  onClick
}) => {
  if (active) {
    return <span>{children}</span>;
  }

  return (
    <a href='#'
       onClick={e => {
         e.preventDefault();
         onClick();
       }}
    >
      {children}
    </a>
  );
};

class FilterLink extends Component {
  componentDidMount() {
    this.unsubscribe = store.subscribe(() =>
      this.forceUpdate()
    );
  }
  
  componentWillUnmount() {
    this.unsubscribe();
  }
  
  render() {
    const props = this.props;
    const state = store.getState();
    
    return (
      <Link
        active={
          props.filter ===
          state.visibilityFilter
        }
        onClick={() =>
          store.dispatch({
            type: 'SET_VISIBILITY_FILTER',
            filter: props.filter
          })
        }
      >
        {props.children}
      </Link>
    );
  }
}

const Footer = () => (
  <p>
    Show:
    {' '}
    <FilterLink
      filter='SHOW_ALL'
    >
      All
    </FilterLink>
    {', '}
    <FilterLink
      filter='SHOW_ACTIVE'
    >
      Active
    </FilterLink>
    {', '}
    <FilterLink
      filter='SHOW_COMPLETED'
    >
      Completed
    </FilterLink>
  </p>
);

const Todo = ({
  onClick,
  completed,
  text
}) => (
  <li
    onClick={onClick}
    style={{
      textDecoration:
        completed ?
          'line-through' :
          'none'
    }}
  >
    {text}
  </li>
);

const TodoList = ({
  todos,
  onTodoClick
}) => (
  <ul>
    {todos.map(todo =>
      <Todo
        key={todo.id}
        {...todo}
        onClick={() => onTodoClick(todo.id)}
      />
    )}
  </ul>
);

const AddTodo = ({
  onAddClick
}) => {
  let input;

  return (
    <div>
      <input ref={node => {
        input = node;
      }} />
      <button onClick={() => {
        store.dispatch({
          type: 'ADD_TODO',
          id: nextTodoId++,
          text: input.value
        });
        input.value = '';
      }}>
        Add Todo
      </button>
    </div>
  );
};

const getVisibleTodos = (
  todos,
  filter
) => {
  switch (filter) {
    case 'SHOW_ALL':
      return todos;
    case 'SHOW_COMPLETED':
      return todos.filter(
        t => t.completed
      );
    case 'SHOW_ACTIVE':
      return todos.filter(
        t => !t.completed
      );
  }
}

class VisibleTodoList extends Component {
  
  componentDidMount() {
    this.unsubscribe = store.subscribe(() =>
      this.forceUpdate()
    );
  }
  
  componentWillUnmount() {
    this.unsubscribe();
  }
  
  render() {
    
    const props = this.props;
    const state = store.getState();
    
    return (
    <TodoList
      todos={
        getVisibleTodos(
          state.todos,
          state.visibilityFilter
        )
      }
      onTodoClick={id =>
        store.dispatch({
          type: 'TOGGLE_TODO',
          id
        })
      }
    />
    );
  }
}

let nextTodoId = 0;
const TodoApp = ({
  todos,
  visibilityFilter
}) => (
  <div>
    <AddTodo />
    <VisibleTodoList />
    <Footer />
  </div>
);

const render = () => {
  ReactDOM.render(
    <TodoApp
      {...store.getState()}
    />,
    document.getElementById('root')
  );
};

store.subscribe(render);
render();