TypeScript

Question 1

How can you override a constructor in TS? (Hard)
Hint: use class decorators

Answer 1

function classDecorator(constructor:T) {
    return class extends constructor {
        newProperty = "new property";
        hello = "override";
    }
}

@classDecorator
class Greeter {
    property = "property";
    hello: string;
    constructor(m: string) {
        this.hello = m;
    }
}

console.log(new Greeter(“world”));

Question 2

How do you define an interface for a callback in TypeScript when you work with Node.js?

Answer 2

interface ICallback {
{ error: Error, result?: number ) : void
});

Question 3

Typescript programs are javascript programs: true or false

Answer 3

True

Question 4

What is an advantage to provide types annotations?

Answer 4

Because they provide intention