After receiving JSON data from a Java backend service called houseguidelines, the information is sent to an Angular application via a service call. I am attempting to iterate over this returned JSON data and add it to an array I have created. Unfortunately, I keep encountering "undefined" errors in the browser console when trying to accomplish this task.
The service call within the Angular application is structured as follows:
export class HouseGuidelinesService {
private readonly houseGuidelinesURL = 'http://localhost8200/homeguidelines';
constructor(private http: HttpClient) {}
getHouseData(houseCode: string): Observable<HouseGuidelineResponse[]> {
return this.http.get<HouseGuidelineResponse[]>(this.houseGuidelinesURL + '/', {headers: {houseCodeList: houseCode}});
}
}
The file responsible for sending data to the service call in the Angular application appears similar to this:
export class HouseComponent implements OnInIt {
houseData: HouseGuidelineResponse[];
houseList = [];
constructor(private activatedRoute: ActivatedRoute, private router: Router, private houseSummaryService: HouseService, private houseGuidelinesService: HouseGuidelinesService ) {}
callHouseService(houseCodeList) {
this.houseGuidelinesService.getHouseData(houseCodeList).subscribe(
(data) => {
this.houseData = data;
console.log('display house guidelines', this.houseData);
console.log('first house data: ', this.houseData[0])
},
(error) => {
console.log('Error Getting House Policy Info!');
}
);
}
}
The structure of the HouseGuidelineResponse object within the Angular application can be represented like this:
export class HouseGuidelineResponse {
id: number;
name: string;
description: string;
settings: HouseSettings[];
}
Although the service call successfully returns JSON data shown in the browser console like below:
dataList: Array(3)
0: {id:1, name: 'house risk 1', description: 'the best guidelines', settings: Array(1)}
1: {id:2, name: 'house risk 2', description: 'the next best guidelines', settings: Array(1)}
2: {id:3, name: 'house risk 3', description: 'the worst guidelines', settings: Array(1)}
Issues arise when trying to iterate over or access elements within the dataList. For example, in the function callHouseService(houseCodeList), the following code snippet causes an error:
for (const value of this.houseData) {
this.houseList.push({
id: value.id
})
}
console.log(this.houseList)
An error message stating "houseData is not iterable" is displayed.
Similarly, attempts to access individual elements within the dataList result in being told that they are undefined. For instance, the code snippets below generate "undefined" errors in the browser console:
console.log('first element: ', this.houseData[0]);
console.log('maybe the first element: ', this.houseData[0].description);
Hence, my question is: how can I effectively iterate over the received JSON dataList to utilize its content and subsequently attribute it to my predefined object?