The data from json is not populated in my angular 8 app

Question

My json looks as follows:

    {
    "content": [
        {
            "id": 1,
            "name": "test name",
            "email": "test@test.com",
            "img_url": "url",
            "field1": [
                {
                    "id": 10,
                    "userId": 1,
                    "registeredAt": "2020-01-09T22:21:23.272",
                    "amount": 200
                }
            ],
            "field2": [
                {
                    "id": 11,
                    "userId": 1,
                    "registeredAt": "2020-01-09T22:21:46.113",
                    "amount": 200
                }
            ],
            "creationDateTime": "2020-01-05T00:00:00Z"
        }
    ],
    "page": 0,
    "size": 30,
    "totalElements": 1,
    "totalPages": 1,
    "last": true
}

and I want to populate with it my angular 8 website.

In my api.service.ts I have:

getMyStructure(): Observable<HttpResponse<MyStructure[]>> { 
    return this.http.get<MyStructure[]>( 
        localUrl, { observe: 'response' }); 
} 

and in app.components.ts I have:

myStructure: MyStructure[] = []; 

getMyStructure() { 
    this.api.getMyStructure() 
    .subscribe(function(resp) { 
        console.log(resp.body.length); //this prints undefined 
        console.log(resp.body) // this prints {content: Array, page: 0, size: 30, totalElements: 1, totalPages: 1, …} 
        this.myStructure = resp.body; 
    }); 
    console.log("after"); 
    console.log(this.myStructure.length); //this prints 0 

Now, myStructure is an interface, that contains:

export interface Shelter {
    id: number;
    name: string;
    email: string;
    img_url: string;
    field1: string[];
    field2: string[];
    creationDateTime: string;
}

but the data inside myStructure somehow is not populated. I have no idea why, can you help me with that?

Answer 1

Your API doesn't return MyStructure[] it returns:

Please chose a better name for the interface

interface SomeStructure {
  content: MyStructure[];
  page: number;
  size: number;
  totalElements: number;
  totalPages: number;
  last: boolean
}

api.service.ts

getMyStructure(): Observable<HttpResponse<SomeStructure>> { 
    return this.http.get<SomeStructure>( 
        localUrl, { observe: 'response' }); 
} 

app.component.ts

myStructure: MyStructure[] = []; 

getMyStructure() { 
    this.api.getMyStructure() 
    .subscribe((resp) => { 
        this.myStructure = resp.body.content; 
    }); 
}

Take note of the arrow function in the subscribe .subscribe((resp) => {

Answer 2

You need to add the console.log inside the subscribe part of the code, otherwise as it gets executed first, you will see it as 0. Change it as,

.subscribe(function(resp) { 
        console.log(resp.body.length); //this prints undefined 
        console.log(resp.body) // this prints {content: Array, page: 0, size: 30, totalElements: 1, totalPages: 1, …} 
        this.myStructure = resp.body; 
        console.log("after"); 
        console.log(this.myStructure.length);  
    }); 

EDIT:

As I see you want to display the content array on the front end, so you need to assign the data as,

 this.myStructure = resp.body.content;