Custom error class in TypeScript

I'd like to create my own error class in TypeScript, extending core Error to provide better error handling and customized reporting. For example, I want to create an HttpRequestError class with url, response and body passed into its constructor, which reponds with Http request to http://example.com failed with status code 500 and message: Something went wrong and proper stack trace.

How to extend core Error class in TypeScript? I've already found post in SO: How do I extend a host object (e.g. Error) in TypeScript but this solution doesn't work for me. I use TypeScript 1.5.3

Any ideas?

Solution 1:

TypeScript 2.1 had a breaking changes regarding Extending built-ins like Error.

From the TypeScript breaking changes documentation

class FooError extends Error {
    constructor(msg: string) {
        super(msg);

        // Set the prototype explicitly.
        Object.setPrototypeOf(this, FooError.prototype);
    }

    sayHello() {
        return "hello " + this.message;
    }
}

Then you can use:

let error = new FooError("Something really bad went wrong");
if(error instanceof FooError){
   console.log(error.sayHello());
}

Solution 2:

Until 1.6 rolls around, I've just been making my own extendable classes.

class BaseError {
    constructor () {
        Error.apply(this, arguments);
    }
}

BaseError.prototype = new Error();

class HttpRequestError extends BaseError {
    constructor (public status: number, public message: string) {
        super();    
    }
}

var error = new HttpRequestError(500, 'Server Error');

console.log(
    error,
    // True
    error instanceof HttpRequestError,
    // True
    error instanceof Error
);