readySignal = () => {
  // let the opener know SVG Edit is ready (now that config is set up)
  const w = window.opener || window.parent
  if (w) {
    try {
      /**
         * Triggered on a containing `document` (of `window.opener`
         * or `window.parent`) when the editor is loaded.
         * @event module:SVGEditor#event:svgEditorReadyEvent
         * @type {Event}
         * @property {true} bubbles
         * @property {true} cancelable
         */
      /**
         * @name module:SVGthis.svgEditorReadyEvent
         * @type {module:SVGEditor#event:svgEditorReadyEvent}
         */
      const svgEditorReadyEvent = new w.CustomEvent('svgEditorReady', {
        bubbles: true,
        cancelable: true
      })
      w.document.documentElement.dispatchEvent(svgEditorReadyEvent)
    } catch (e) { /* empty fn */ }
  }
}
@fires module:svgcanvas.SvgCanvas#event:svgEditorReady
@returns {void}