Typescript, class type is not assignable to index interface

Question

I have a class that has some public properties and I would like to pass it to a function with a generic argument of an index interface type, but I get an compiler error that says Argument of type 'Car' is not assignable to parameter of type '{ [k: string]: unknown; }'.

Could someone explain what is wrong because I assume all Classes are of type object?!!

class Car {

  name: string | undefined;

}

function toStr <T extends { [k: string]: unknown }>(i: T) {
  return i.toString();
}


const jeep = new Car();
jeep.name = 'jeep';

toStr(jeep);

Answer 1

Just use object instead { [k: string]: unknown }.

class Car {

  name: string | undefined;

}

function toStr <T extends object>(i: T) {
  return i.toString();
}


const jeep = new Car();
jeep.name = 'jeep';

const result = toStr(jeep);