NativeScript/e2e/ui-tests-app/app/bottom-navigation/bottom-navigation-view-model.ts

import { GridLayout } from "tns-core-modules/ui/layouts/grid-layout";
import { Label } from "tns-core-modules/ui/label";
import { Observable } from "tns-core-modules/data/observable";
import { TabStripItem } from "tns-core-modules/ui/tab-navigation-base/tab-strip-item";
import { TabContentItem } from "tns-core-modules/ui/tab-navigation-base/tab-content-item";

export class BottomNavigationViewModel extends Observable {
    private itemsCount: number = 1;
    public tabStripItems = new Array<TabStripItem>();
    public tabContentItems = new Array<TabContentItem>();

    constructor() {
        super();
        this.createItems();
        this.createItems();
    }

    public createItems() {
        console.log("Create item");

        const _tabStripItems = new Array<TabStripItem>();
        const _tabContentItems = new Array<TabContentItem>();

        for (let index = 0; index < this.itemsCount; index++) {
            _tabStripItems.push(this.createTabStripItem(index));
            _tabContentItems.push(this.createContentStripItem(index));
        }

        this.tabStripItems = _tabStripItems;
        this.tabContentItems = _tabContentItems;
        this.itemsCount++;
    }

    public removeLastItem() {
        console.log("Remove item");
        this.tabStripItems.pop();
        this.tabContentItems.pop();
    }

    private createTabStripItem(index: number): TabStripItem {
        const item = new TabStripItem();
        item.title = "Item " + index;
        item.iconSource = "res://icon";

        return item;
    }

    private createContentStripItem(index: number): TabContentItem {
        const contentItem = new TabContentItem();
        const label = new Label();
        const gridlayout = new GridLayout();
        label.text = "Content Item " + index;
        gridlayout.addChild(label);
        contentItem.content = gridlayout;

        return contentItem;
    }
}