Typescript - How to convert Error Response to Error Object?

Question

I want to log exceptions generated in typescript to a log file (text file). I want to log information like description,message,name,number,stack. I have written Model, API Controller and logic to write the data into text file.

However I want to map Error Response generated after get, post,put operation in typescript. I have written below Interface

export interface TypeScriptException {
    Description: string;
    Message: string;
    Name: string;
    Number: string;
    ErrorStack: string;
}

When handleError method is called after Post in below example, how do I assign values from Error Response to my TypeScriptException object?

post(url: string, model: any): Observable<any> {

    let body = JSON.stringify(model);
    let headers = new Headers({ 'Content-Type': 'application/json' });
    let options = new RequestOptions({ headers: headers });
    return this._http.post(url, body, options)
        .map((response: Response) => <any>response.json())
        .catch(this.handleError);
}

private handleError(error: Response) {

    let typeScriptException: TypeScriptException;

    //What to do here

}

If error return object. you can convert using new Error(error) . I Haven't reseted this. — Suresh Kumar Ariya
– Suresh Kumar Ariya, Commented Nov 23, 2018 at 7:42
if you are trying to handle http errors , then you always has an best practice to create a custom ErrorInterceptor from HttpInterceptor which can be injected into providers — Joel Joseph
– Joel Joseph, Commented Nov 23, 2018 at 8:26

SiddAjmera · Accepted Answer · 2018-11-23 09:02:10Z

1

In case of error, you get an instance of type HttpErrorResponse. You can extract fields from this instance and assign it to the typeScriptException variable that you've defined. You will have to leverage the details that are provided in this instance and set the fields on typeScriptException accordingly.

Here's what an instance of HttpErrorResponse looks like:

Keeping all the fields it has in mind, you can assign some of them to your typeScriptException, something along the lines of this:

private handleError(error: HttpErrorResponse) {
  let typeScriptException: TypeScriptException;
  let { message, name, ok, status, statusText, url } = error;
  //What to do here?
  typeScriptException = {
    Description: `${name} - ${message}`, // OR SOMETHING
    Message: message
    Name: name,
    Number: status, // OR SOMETHING
    ErrorStack: statusText // OR SOMETHING
  }
}

edited Nov 23, 2018 at 9:02

answered Nov 23, 2018 at 7:52

SiddAjmera

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4 Comments

captainsac Over a year ago

Getting compile error "Type 'Response' has no property 'message' and no string index signature." and "Type 'Response' has no property 'name' and no string index signature."

SiddAjmera Over a year ago

My bad. Use (error: HttpErrorResponse) instead of (error: Response)

Fiddle Freak Over a year ago

I'm getting Cannot find name 'HttpErrorResponse'

SiddAjmera Over a year ago

@FiddleFreak You need to import { HttpErrorResponse } from '@angular/common/http';

Muhammed Albarmavi · Accepted Answer · 2018-11-23 10:47:33Z

0

In my case I use throw method to throw new Error

import {Observable} from "rxjs"

private handleError(res: HttpErrorResponse) {
  Observable.throw(new Error({message:res.message,code:res.status}));
}

or if you want to get all property of Response

private handleError(res: HttpErrorResponse) {
  Observable.throw(new Error({...res}));
}

edited Nov 23, 2018 at 10:47

answered Nov 23, 2018 at 7:53

Muhammed Albarmavi

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1 Comment

captainsac Over a year ago

what is the type of Rx?

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