Get rails associated objects with React

Question

After setup a simple post associated user model with rails i'd like to get the post owner avatar with react but all that i get this error:

TypeError: Cannot read property 'username''avatar' etc.. of undefined

I've tried to get the associated post user on fetching the post

async getPost() {
    // this.setState({showProgress: true})

let {
  match: { params }
} = this.props;

const response = await axios
  .get(`/posts/${params.id}`, {
    headers: {
      Accept: "application/json",
      "Content-Type": "application/json"
    },
    credentials: "same-origin"
  })

  .then(result => {
    this.setState({
      title: result.data.post.title,
      user: result.data.post.user.username,
      user: result.data.post.user,

     url: result.data.post.user.avatar.post.url
    });
  })
  .catch(error => {
    console.error(error);
  });


}

but Still showing error on the log and the user that is filled with the post is the user_id

So, someone has any hint to spare about this?

could you show the result of console.log(result) so that it will be easy to debug. — Kamal Pandey
– Kamal Pandey, Commented Jun 5, 2019 at 4:21

quyetdc · Accepted Answer · 2019-06-05 04:39:23Z

3

It is because your returned data does not include user information. In your ajax call response, you cannot query as if you are in rails controller.

In your case, you should return user information together with post in your controller action.

post = Post.find(params[:id])
user = post.user
post = post.as_json
post[:user] = user.as_json

render json: { post: post }

If you need users information for multiple posts, you can use eager loading in your rails controller action

@posts = Post.includes(:user).all.map do |post|
           post_json = post.as_json
           post_json[:user] = post.user.as_json
           post_json
         end

render json: { posts: @posts }

answered Jun 5, 2019 at 4:39

quyetdc

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1 Comment

Danks Over a year ago

quyetdc that's it, thank you very much for your answer!

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