Files
angular/aio/content/examples/http/src/app/http-error-handler.service.ts
George Kalpakas 7c0f11789b style(docs-infra): fix docs examples for tslint rules related to whitespace (#38143)
This commit updates the docs examples to be compatible with the `align`,
`space-before-function-paren` and `typedef-whitespace` tslint rules.

This is in preparation of updating the docs examples `tslint.json` to
match the one generated for new Angular CLI apps in a future commit.

PR Close #38143
2020-07-31 11:00:05 -07:00

49 lines
1.8 KiB
TypeScript

import { Injectable } from '@angular/core';
import { HttpErrorResponse } from '@angular/common/http';
import { Observable, of } from 'rxjs';
import { MessageService } from './message.service';
/** Type of the handleError function returned by HttpErrorHandler.createHandleError */
export type HandleError =
<T> (operation?: string, result?: T) => (error: HttpErrorResponse) => Observable<T>;
/** Handles HttpClient errors */
@Injectable()
export class HttpErrorHandler {
constructor(private messageService: MessageService) { }
/** Create curried handleError function that already knows the service name */
createHandleError = (serviceName = '') => {
return <T>(operation = 'operation', result = {} as T) =>
this.handleError(serviceName, operation, result);
}
/**
* Returns a function that handles Http operation failures.
* This error handler lets the app continue to run as if no error occurred.
* @param serviceName = name of the data service that attempted the operation
* @param operation - name of the operation that failed
* @param result - optional value to return as the observable result
*/
handleError<T>(serviceName = '', operation = 'operation', result = {} as T) {
return (error: HttpErrorResponse): Observable<T> => {
// TODO: send the error to remote logging infrastructure
console.error(error); // log to console instead
const message = (error.error instanceof ErrorEvent) ?
error.error.message :
`server returned code ${error.status} with body "${error.error}"`;
// TODO: better job of transforming error for user consumption
this.messageService.add(`${serviceName}: ${operation} failed: ${message}`);
// Let the app keep running by returning a safe result.
return of( result );
};
}
}