Question

我有一个连接到商店的组件，传递到该组件的道具之一是post，它是一个对象。我想将post.id传递给mapStateToProps，以便可以观察对帖子评论数组的更改。

这是我到目前为止尝试过的

const mapStateToProps = state => ({
  myProfile: state.users.myProfile,
  comments: state.activity.posts[this.postID].comments,
});

const mapStateToProps2 = state => {
  const id = this.postID;

  return {
    myProfile: state.users.myProfile,
    comments: state.activity.posts[id].comments,
  };
};

有人知道我能做到吗，有什么想法吗？

欢呼

编辑这是我最后进行的实现：

 const mapStateToProps = (state, ownProps) => { 
    const { navigation } = ownProps; 
    const navPost = navigation.getParam('post', {}); 

    const postComments = state.activity.posts.filter( post => post.id === navPost.id );

    return { 
       myProfile: state.users.myProfile, 
       comments: postComments[0].comments, 
    }; 
};

Answer 1

this关键字很可能引用了错误的范围，并且找不到postId。

要么在状态中分配ID，然后像state.postId那样访问它，要么将ID传递给组件的属性，然后像这样使用它：

function mapStateToProps(state, ownProps) {
  const { visibilityFilter } = state
  const { id } = ownProps
  const todo = getTodoById(state, id)

  // component receives additionally:
  return { todo, visibilityFilter }
}

// Later, in your application, a parent component renders:
;<ConnectedTodo id={123} />
// and your component receives props.id, props.todo, and props.visibilityFilter

来源：https://react-redux.js.org/using-react-redux/connect-mapstate

将类道具传递给mapStateToProps

1 个答案: