Typescript: missing model property

[alfonsodev]

Thanks for this useful package,
One feature request,
it would be nice to have model property typed, instead it falls into [propName: string]: any;

tree-model-js/types/index.d.ts

Line 38 in 1ac126a

[propName: string]: any;

Example:

type BlockTreeObject = Readonly<{
  id: string;
  parent?: string;
  content?: string;
  children?: ReadonlySet<BlockTreeObject>;
}>;
  
  constructor(data: TreeModel.Model<BlockTreeObject>) {
    this.tree = new TreeModel();
    this.rootNode = this.tree.parse(data);
    this.rootNode.model.id = "this should fail as model is typed read only";
  }
  

Would it be easy to add ?
thanks you!