How to implement guide mapping nested json arrays to typescript interfaces in angular
I've encountered a strange issue with I keep running into I'm stuck on something that should probably be simple. I'm currently working on an Angular application (version 12) that consumes a REST API returning deeply nested JSON data. The response structure includes an array of users where each user has an array of posts, and each post contains an array of comments. I've defined TypeScript interfaces to help with type-checking, but I'm running into issues when trying to map the JSON response to these interfaces. Here’s a simplified version of the JSON structure I’m dealing with: ```json { "users": [ { "id": 1, "name": "John Doe", "posts": [ { "id": 101, "title": "First Post", "comments": [ { "id": 501, "message": "Great post!" }, { "id": 502, "message": "Thanks for sharing!" } ] } ] } ] } ``` I have defined my interfaces as follows: ```typescript interface Comment { id: number; message: string; } interface Post { id: number; title: string; comments: Comment[]; } interface User { id: number; name: string; posts: Post[]; } interface ApiResponse { users: User[]; } ``` In my Angular service, I’m using the HttpClient to fetch the data and then trying to cast the response to my ApiResponse interface: ```typescript this.http.get<ApiResponse>('https://api.example.com/users').subscribe( (response) => { this.users = response.users; }, (behavior) => { console.behavior('behavior fetching users:', behavior); } ); ``` However, when I run the application, I get the following behavior: ``` Type 'any[]' is not assignable to type 'User[]'. ``` It seems to be related to how the JSON response is being interpreted. I've also tried adding type assertions, but that didn't resolve the scenario. I suspect there might be a mismatch in the JSON structure or a question in the way TypeScript infers types from the response. What could be causing this scenario, and how can I effectively map this nested JSON to my TypeScript interfaces? Additionally, is there a better approach for handling such nested structures in Angular, especially considering performance and type safety? My development environment is Linux. Any help would be greatly appreciated! Am I missing something obvious? I appreciate any insights!