init1

    package Foo
        type Bar is private;
        procedure Initialize (Item : in out Bar); 
    private
        type Bar is record
            Baz : Integer;
            Qux : Float;
        end record;
    end Foo;

    class Bar {
        constructor() {
            this.Baz = 420;
            this.Qux = 1337.69;
        }
    }
    export function Initialize() {
        return new Bar();
    }

    import { Initialize } from 'module';
    let myBar = Initialize();

    myBar.Baz = 42069; // works just fine
    Object.keys(myBar).forEach(console.log); // you can iterate parameters.
    myBar.Quux = 'Corge'; // add new parameters
    delete myBar.Baz; // I hope no functions rely on this...