Can I use rxjs to filter an Observable against a string array of id's

Question

Im setting up Access Control for an angular app and have modeled my User object like this: -User --firstName --phoneNumber --posts[] <--- String array of post id's

getPosts(): Observable<any[]> {
    return this.postsCollection.snapshotChanges().pipe(
      map((actions) => {
        return actions.map((a) => {
          const data = a.payload.doc.data();
          const data2 = { id: a.payload.doc.id, ...data};
          this.hasPostAccess(data2);
          return { id: a.payload.doc.id, ...data};
        });
      })
    );
  }

  private hasPostAccess(data: any) {
    const inspect = obj => {
      for (const prop in obj) {
        if (obj.hasOwnProperty(prop)) {
          // console.log(`${prop}: ${obj[prop]}`);
          if (prop === 'id') {
            console.log(obj[prop]);
            const PostId = obj[prop];
            const currentUser = JSON.stringify(localStorage.getItem('user'));
            if (currentUser.search(PostId) === -1) {
              console.log('Denied: ' + PostId);
            } else {
              console.log('Allowed: ' + PostId);
            }
            console.log('Current USER: ' + JSON.stringify(currentUser));
            // if (currentUser(PostId) > -1) {
            //   console.log('Allowed: ' + PostId);
            // } else {
            //   console.log('Denied: ' + PostId);
            // }
          }
        }
      }
    };
    inspect(data);
  }

I want to show all posts that belong to the user. So when I subscribe to the getPosts Observable, this must filter the posts and return only the posts id's that are stored in the User's post array.

Where is the problem? Are you expecting us to do your work for you? How to ask — Mike Tung
– Mike Tung, Commented May 21, 2019 at 12:52
No Mike, just wanted to know how this can be done with an Observable without using the prop inspection. I am new to rxjs. :) — Badger 29
– Badger 29, Commented May 21, 2019 at 13:16

Badger 29 · Accepted Answer · 2019-05-22 20:07:52Z

0

getPosts(): Observable<any[]> {
    const currentUser: User = JSON.parse(localStorage.getItem('user'));
    const userPosts  = currentUser.posts;
    return this.postsCollection.snapshotChanges().pipe(
      map((actions) => {
        return actions.map((a) => {
          const data = { id: a.payload.doc.id, ...data};
          const filteredPosts = _.filter(data, (p) => 
          _.includes(currentUser, p.postId));
          return filteredPosts;
        });
      })
    );
  }

answered May 22, 2019 at 20:07

Badger 29

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