TypeScript Mixins -

typescript 2.2 added mixins. however, when try run sample code, shows error, saying base not constructor function type.

class point {     constructor(public x: number, public y: number) {} }  class person {     constructor(public name: string) {} }  type constructor<t> = new(...args: any[]) => t;  function tagged<t extends constructor<{}>>(base: t) {     return class extends base { //error here         _tag: string;         constructor(...args: any[]) {             super(...args);             this._tag = "";         }     } }  const taggedpoint = tagged(point);  let point = new taggedpoint(10, 20); point._tag = "hello";  class customer extends tagged(person) {     accountbalance: number; }  let customer = new customer("joe"); customer._tag = "test"; customer.accountbalance = 0; 

is there needs changed in declaration of constructor remove error?

(related, if ts team reads this, handbook on mixins appears out of date.)