[Redux] Generating Containers with connect() from React Redux (VisibleTodoList)

Learn how to use the that comes with React Redux instead of the hand-rolled implementation from the previous lesson.

Code to be refactored:

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

VisibleTodoList.contextTypes = {
  store: React.PropTypes.object
};

In the code, we handle the 'context', subscribe state and unsubscribe. Also we need to always remember write 'contextTypes'. There are lots of things todo.

Actually we can use 'ReactRedux' libaray to simpy our life:

'ReactRedux' libaray's connect() fucntion also pass the context down to the component. 

VisibleTodoList:

So get the todos and write into mapStateToProps function:

const mapStateToProps = (state) => {
  return {
    todos: getVisibleTodos(
      state.todos,
      state.visibilityFilter
    )
  };
};

then get onTodoClick dispatch function to the mapDispatchToProps function:

const mapDispatchToProps = (dispatch) => {
  return {
    onTodoClick: (id) => {
      dispatch({
        type: 'TOGGLE_TODO',
        id
      });
    }
  };
};

then we can use 'connect()()' function to connect state, dispatch action and Render component together:

const { connect } = ReactRedux;
const VisibleTodoList = connect(
  mapStateToProps,
  mapDispatchToProps
)(TodoList);

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

code:

const mapStateToProps = (state) => {
  return {
    todos: getVisibleTodos(
      state.todos,
      state.visibilityFilter
    )
  };
};

const mapDispatchToProps = (dispatch) => {
  return {
    onTodoClick: (id) => {
      dispatch({
        type: 'TOGGLE_TODO',
        id
      });
    }
  };
};

const { connect } = ReactRedux;
const VisibleTodoList = connect(
  mapStateToProps,
  mapDispatchToProps
)(TodoList);