How to use the @hpcc-js/common.Button function in @hpcc-js/common

import { BlankLayer } from "./Blank";
import { GMapLayer } from "./GMap";
import { MapBoxLayer } from "./MapBox";
import { OpenStreetLayer } from "./OpenStreet";
import { ILayer, TileLayer } from "./TileLayer";

import "../../src/leaflet/Leaflet.css";

export class Leaflet extends HTMLWidget {

    protected _leafletElement;
    private _leafletMap: Map;

    protected _iconBar = new IconBar()
        .buttons([
            new Button().faChar("fa-plus").tooltip("Zoom in")
                .on("click", () => {
                    this.zoomPlus();
                }),
            new Button().faChar("fa-minus").tooltip("Zoom out")
                .on("click", () => {
                    this.zoomMinus();
                }),
            new Spacer(),
            new Button().faChar("fa-arrows-alt").tooltip("Zoom to fit")
                .on("click", () => {
                    this.zoomToFit();
                })
        ])
        ;

    _blankLayer = new BlankLayer();

const samplePath = "https://raw.githack.com/hpcc-systems/Visualization/master/demos/gallery/";

export class SampleCarousel extends ChartPanel {

    _samples = [];
    _sampleWidgets = [];
    _sampleCarousel = new Carousel();

    _prevButton = new Button()
        .faChar("fa-step-backward")
        .on("click", () => {
            this.decIdx();
            this.renderSample();
        });
    _playPauseButton = new Button()
        .faChar("fa-pause")
        .on("click", () => {
            this._playPauseButton.faChar(this.isPaused() ? "fa-pause" : "fa-play").lazyRender();
        });
    _nextButton = new Button()
        .faChar("fa-step-forward")
        .on("click", () => {
            this.incIdx();
            this.renderSample();
        });

    constructor() {
        super();
        this.visit(config.samples);
        this.shuffle();
        this._sampleWidgets = [];

if (this._contextMenu.open({
                target: node,
                currentTarget: node,
                clientX: rect.left,
                clientY: rect.bottom
            })) {
            }
        });

    private _removeButton = new Button().faChar("fa-minus").tooltip("Remove...")
        .enabled(false)
        .on("click", () => {
            this.remove();
        });

    private _cloneButton = new Button().faChar("fa-clone").tooltip("Clone...")
        .enabled(false)
        .on("click", () => {
            if (this._selectedDS2) {
                if (this._selectedDS2 instanceof Databomb) {
                    this.add(new Databomb()
                        .format(this._selectedDS2.format())
                        .payload(this._selectedDS2.payload())
                    );
                } else if (this._selectedDS2 instanceof Form) {
                    this.add(new Form()
                        .fromDDL(this._selectedDS2.toDDL())
                    );
                } else if (this._selectedDS2 instanceof LogicalFile) {
                    this.add(new LogicalFile(this._ec)
                        .url(this._selectedDS2.url())
                        .logicalFile(this._selectedDS2.logicalFile())

import { Button, Spacer, ToggleButton, Widget } from "@hpcc-js/common";
import { ScopeGraph, Workunit } from "@hpcc-js/comms";
import { Table } from "@hpcc-js/dgrid";
import { Graph as GraphWidget, Subgraph, Vertex } from "@hpcc-js/graph";
import { Carousel, ChartPanel } from "@hpcc-js/layout";
import { hashSum } from "@hpcc-js/util";
import { WUGraphLegend } from "./WUGraphLegend";
import { WUScopeController } from "./WUScopeController";

import "../src/WUGraph.css";

export class WUGraph extends ChartPanel {

    private _partialAll = new Button().faChar("fa-window-restore").tooltip("Partial All")
        .on("click", () => {
            this.stateClick(this._partialAll);
        });

    private _maxAll = new Button().faChar("fa-window-maximize").tooltip("Max All")
        .on("click", () => {
            this.stateClick(this._maxAll);
        });

    private _toggleGraph = new ToggleButton().faChar("fa-chain").tooltip("Graph")
        .selected(true)
        .on("click", () => {
            this.viewClick(this._toggleGraph);
        });

    private _toggleActivities = new ToggleButton().faChar("fa-table").tooltip("Activitiies")