pass server side errors to client side typescript using vs code

Question

Hi All, am having a class with businesslogic validate the input paramerters if true save the data else return the error msg to client side typescript and show an alert ex: name already exists in DB need to show particular error msg to angular alert Data already exists using vs code async and await

P K · Answer

You can simply returns the error message with status code from backend API response to frontend API Like public class Response { public object Data { get ; set ; } public string Message { get ; set ; } public int Status { get ; set ; } public ResponseWrapper() { } public Response( object data, string message, int status) { Status = status; Message = message; Data = data; } } In response you can return message with status code from your API like if record exists then returns response as below or whatever your check return msg according to that returns new Response(data,'Already exists',StatusCodes.Status500InternalServerError); you need to handle it based on API response at front end in angular where your calling API method like save(payload) { service.saveAPI(payload).subscribe(response => { if (response.body.status == 200) { this .data= response.body.data; } else { alert(response.body.message); } }, error => { alert(error.message); }); }

Kiran Mohanty · Answer

Hi, You can throw exception from server side based on your condition and then in Angular , add alert in error callback method as below. if (condition){ //no error logic } else { throw new Exception( "Name already exist in DB" ); } Angular code this .service.apiAction() .subscribe( result => { // Handle no error result }, error => { alert(error); } );