Combine the results of two observable in angular

Updated on July 21, 2020     Kisan Patel

How to combine the results of two observable in angular?

Use forkJoin to join multiple results.

// Get all posts
// Get the user of each post
// Get the todos for each user
postData$ = this.http.get<Post[]>(this.postUrl).pipe(
    switchMap(posts =>
        forkJoin(
             posts.map(post =>
                  forkJoin([
                        this.http.get<User>(`${this.userUrl}/${post.userId}`),
                        this.http.get<ToDo[]>(`${this.todoUrl}?userId=${post.userId}`)
                     ]).pipe(
                          map(([user, todos]) => ({
                                    post: post,
                                    userName: user.name,
                                    todos: todos
                          }))
                 )
             )
        )
   )
);