TypeScript pass by ref parameter

In C# it is possible to pass parameters by reference. For instance:

    private void Add(ref Node node)
    {
        if (node == null)
        {
            node = new Node();
        }
    }
    Add(ref this.Root);

this.Root would not be null after doing Add(ref this.Root)

From what I've seen from TypeScript, it is not possible to pass parameters by reference. This code:

    private addAux(node: Node): void {
        if (node === undefined) {
            node = new Node();
        }
    }
    addAux(this._root);

After doing addAux(this._root), this._root will still be undefined because a copy of it will be passed into addAux.

Is there a workaround to have the same feature as the ref keyword from C# in TypeScript?