How to use the vega-scenegraph.RenderType.Canvas function in vega-scenegraph

export default function View(spec, options) {
  var view = this;
  options = options || {};

  Dataflow.call(view);
  if (options.loader) view.loader(options.loader);
  if (options.logger) view.logger(options.logger);
  if (options.logLevel != null) view.logLevel(options.logLevel);

  view._el = null;
  view._elBind = null;
  view._renderType = options.renderer || RenderType.Canvas;
  view._scenegraph = new Scenegraph();
  var root = view._scenegraph.root;

  // initialize renderer, handler and event management
  view._renderer = null;
  view._tooltip = options.tooltip || defaultTooltip,
  view._redraw = true;
  view._handler = new CanvasHandler().scene(root);
  view._preventDefault = false;
  view._timers = [];
  view._eventListeners = [];
  view._resizeListeners = [];

  // initialize dataflow graph
  var ctx = runtime(view, spec, options.functions);
  view._runtime = ctx;

export default function View(spec, options) {
  var view = this;
  options = options || {};

  Dataflow.call(view);
  if (options.loader) view.loader(options.loader);
  if (options.logger) view.logger(options.logger);
  if (options.logLevel != null) view.logLevel(options.logLevel);

  view._el = null;
  view._elBind = null;
  view._renderType = options.renderer || RenderType.Canvas;
  view._scenegraph = new Scenegraph();
  var root = view._scenegraph.root;

  // initialize renderer, handler and event management
  view._renderer = null;
  view._tooltip = options.tooltip || defaultTooltip,
  view._redraw = true;
  view._handler = new CanvasHandler().scene(root);
  view._preventDefault = false;
  view._timers = [];
  view._eventListeners = [];
  view._resizeListeners = [];

  // initialize event configuration
  view._eventConfig = initializeEventConfig(spec.eventConfig);

export default function View(spec, options) {
  var view = this;
  options = options || {};

  Dataflow.call(view);
  view.loader(options.loader || view._loader);
  view.logLevel(options.logLevel || 0);

  view._el = null;
  view._renderType = options.renderer || RenderType.Canvas;
  view._scenegraph = new Scenegraph();
  var root = view._scenegraph.root;

  // initialize renderer, handler and event management
  view._renderer = null;
  view._redraw = true;
  view._handler = new CanvasHandler().scene(root);
  view._eventListeners = [];
  view._preventDefault = false;
  view._resizeListeners = []

  // initialize dataflow graph
  var ctx = runtime(view, spec, options.functions);
  view._runtime = ctx;
  view._signals = ctx.signals;
  view._bind = (spec.bindings || []).map(function(_) {

export default async function(scaleFactor, opt) {
  const r = await renderHeadless(this, RenderType.Canvas, scaleFactor, opt);
  return r.canvas();
}

export default function(scaleFactor) {
  return renderHeadless(this, RenderType.Canvas, scaleFactor)
    .then(function(renderer) { return renderer.canvas(); });
}