Create a new object from type parameter in generic class

Question

I'm trying to create a new object of a type parameter in my generic class. In my class View, I have 2 lists of objects of generic type passed as type parameters, but when I try to make new TGridView(), TypeScript says:

Could not find symbol 'TGridView

This is the code:

module AppFW {
    // Represents a view
    export class View<TFormView extends FormView, TGridView extends GridView> {
        // The list of forms 
        public Forms: { [idForm: string]: TFormView; } = {};

        // The list of grids
        public Grids: { [idForm: string]: TGridView; } = {};

        public AddForm(formElement: HTMLFormElement, dataModel: any, submitFunction?: (e: SubmitFormViewEvent) => boolean): FormView {
            var newForm: TFormView = new TFormView(formElement, dataModel, submitFunction);
            this.Forms[formElement.id] = newForm;
            return newForm;
        }

        public AddGrid(element: HTMLDivElement, gridOptions: any): GridView {
            var newGrid: TGridView = new TGridView(element, gridOptions);
            this.Grids[element.id] = newGrid;
            return newGrid;
        }
    }
}

Can I create objects from a generic type?

Answer 1

To create a new object within generic code, you need to refer to the type by its constructor function. So instead of writing this:

function activatorNotWorking<T extends IActivatable>(type: T): T {
    return new T(); // compile error could not find symbol T
}

You need to write this:

function activator<T extends IActivatable>(type: { new(): T ;} ): T {
    return new type();
}

var classA: ClassA = activator(ClassA);

See this question: Generic Type Inference with Class Argument