How to send a string array in HttpClient post method in Angular 14?

November 11, 2022

I try to send a string array with HttpClient post method to my backend.

getAnnouncementsByIds(ids: string[]): Observable<Announcement[]> {
  return this.http.post<Announcement[]>(`${environment.serverUrl}${this.urlGetAnnouncementsByIds}`, ids);
}

Current error is: Http Status 400 with message "JSON parse error: Cannot deserialize value of type [Ljava.lang.String; from Integer value (token JsonToken.VALUE_NUMBER_INT);

I tried different things to make it work:

add the number array as stringified value to HttpParams
add a header with "Content-Type": "application/json"

i cant find a solution how to send an array as body in an Http Post request.

Can someone help me? Im sure it should be pretty easy.

>Solution :

You can make a object like this:

export interface IdList{
 ids: string[]
}

First option:

getAnnouncementsByIds(ids: string[]): Observable<Announcement[]> {
  const rq = {ids = ids} as IdList
  return this.http.post<Announcement[]>(`${environment.serverUrl}${this.urlGetAnnouncementsByIds}`, rq);
}

Second option:

getAnnouncementsByIds(ids: IdList): Observable<Announcement[]> {
  return this.http.post<Announcement[]>(`${environment.serverUrl}${this.urlGetAnnouncementsByIds}`, ids);
}