Custom error class in TypeScript

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
);

I am using TypeScript 1.8 and this is how I use custom error classes:

UnexpectedInput.ts

class UnexpectedInput extends Error {

  public static UNSUPPORTED_TYPE: string = "Please provide a 'String', 'Uint8Array' or 'Array'.";

  constructor(public message?: string) {
    super(message);
    this.name = "UnexpectedInput";
    this.stack = (<any> new Error()).stack;
  }

}

export default UnexpectedInput;

MyApp.ts

import UnexpectedInput from "./UnexpectedInput";

...

throw new UnexpectedInput(UnexpectedInput.UNSUPPORTED_TYPE);

For TypeScript versions older than 1.8, you need to declare Error:

export declare class Error {
  public message: string;
  public name: string;
  public stack: string;
  constructor(message?: string);
}

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());
}