@jaricardodev/ews-javascript-api/src/js/Search/ItemGroup.ts

EWS Managed api in JavaScript

import {EwsLogging} from "../Core/EwsLogging"
import {Item} from "../Core/ServiceObjects/Items/Item";
export class ItemGroup<TItem extends Item> {
    GroupIndex: string;
    Items: TItem[] = [];//System.Collections.ObjectModel.Collection<TItem>;
    constructor(groupIndex: string, items: TItem[]) {
        EwsLogging.Assert(
            items != null,
            "ItemGroup.ctor",
            "items is null");

        this.GroupIndex = groupIndex;
        this.Items = items; //new Collection<TItem>(items);
    }
}