CODEWITHSUNDEEP
node.jsangularexpressmongoose
user6680
user6680

Reputation: 139

GET request works on backend with Postman, but returns null to frontend

I have a GET request where if I add the creator to the post as a param like api/watchlist/?creator=5dac9d3567aca81e40bfc0 and test it in Postman, the results return all posts by that creator with the following code correctly.

app.js

  app.get('/api/watchlist',(req, res, next)=>{
  Watching.find({ creator: req.query.creator})
  .then(documents => {
    console.log("Creator value: " + req.query.creator);
   res.status(200).json({
     message: 'User\'s watchlist items retrieved!',
     posts: documents

  });

   });
   });

If I try and pull the GET request into angular, then it returns nothing. Also the front end when I open the relevant webpage says frontend is saying ERROR TypeError: "retrievedData.posts is undefined" getWatchListItems watch-list.service.ts:72

watch-list.service.ts

getWatchListItems(creator: string) {

this.http
  .get<{ message: string; posts: any; maxPosts: number; watchlist: string }>(
    "http://localhost:3000/api/watchlist?creator=" + creator
  )
  .pipe(
    map(retrievedData  => {
      console.log(retrievedData.watchlist);
               return {
        posts: retrievedData.posts.map(post => {
      console.log(retrievedData.watchlist);
          return {
        title: post.title,
        cost: post.cost,
        listingOwner: post.listingOwner,
        id: post._id
          };

        }),
        maxPosts: retrievedData .maxPosts
      };
    })
  )
  .subscribe(transformedPostData => {
    console.log(transformedPostData);
    this.posts = transformedPostData.posts;
    this.postsUpdated.next({
      listing: [...this.posts],
      postCount: transformedPostData.maxPosts
    });
  });

}

watching.component.ts

 ngOnInit() {
    this.userId = localStorage.getItem("userId: ");
    //  this.userId = this.authService.getUserId();
    this.watchListService.getWatchListItems(this.userId);
    this.postsSub = this.watchListService
      .getPostUpdateListener()
      .subscribe((postData: { listing: Watching[]; postCount: number }) => {

        this.totalPosts = postData.postCount;
        this.posts = postData.listing;

      });

  }

Upvotes: 0

Views: 1176

Answers (1)

SuleymanSah
SuleymanSah

Reputation: 17898

You are sending the create as a route parameter in angular service.

So you need to modify your api like this:

app.get('/api/watchlist/:creater', (req, res, next) => {
  Watching.find({ creator: req.params.creator })
    .then(documents => {
      console.log("Creator value: ", req.params.creator);
      res.status(200).json({
        message: 'User\'s watchlist items retrieved!',
        watchlist: documents
      });
    });
});

And if you dont want to change the api, you should send the creator as a query param like this:

return this.http
      .get<{ message: string; posts: any; maxPosts: number }>(
        "http://localhost:3000/api/watchlist?creator=" + creator
      )

After this, you must handle the response data in angular, and transform to your needs.

Can you update the question, by including this console.log result with this code? (as I know in the service you don't need to subscribe, you are subscribing in your component)

getWatchListItems(creator: string) {

  return this.http("http://localhost:3000/api/watchlist?creator=" + creator)
    .pipe(
      map(retrievedData => {
        console.log("retrievedData: ", retrievedData);
        //todo: transform retrievedData

        return retrievedData;
      })
    )
}

Don't forget your api returns the data in this format, so you should 

{
  "watchlist": ...
   "message": ...
}

Upvotes: 1

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