Dynamic declared prototypes props in typescript

I want typescript to reconize the dynamicly added prototyps.

Here is my code so you would know What i mean.

class Test {
name: string= "";
lastName: string = "";

}

Then I have a Method that generate props dynamicly

const public_m = (...Items: any[]) => {
  try {
    Items.forEach(Item => {
      let keys = (
        Item.tb
          ? Item.tb().props // if there is a db Mapped Keys takes then otherwise Object.Keys
          : Object.keys(new Item())
      ).map(x => x.columnName || x);
      // create statis "n" methods that return new objects eg Test.n()
      Item["n"] = (...args: any[]) =>
        new Item(...args);
      // create clone Method that clone the object
      Item.prototype.clone = function () {
        let item = Item.n();
        for (let k in this) item[k] = this[k];
        return item;
      };
      // generate public set methods eg for name => Name() => Object(Test)
      keys.forEach(x => {
        let n =
          x[0].toUpperCase() + x.substring(1);
        if (!Item.prototype[n])
          Item.prototype[n] = function (v: any) {
            if (!this)
              throw "this is null " + Item;
            this[x] = v;
            return this;
          };
      });
    });
  } catch (e) {
    console.error(e, Items);
  }
};

public_m(Test);

export default Test;

Lastly I am using it as fellow

let test = Test.n().Name("test").LastName("test");

The issue is that typescript wont see those methods Name() and LastName()etc.. as those are create dynamicly