TypeScript mixins example

example.ts

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 {
        _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;