ionic-framework/core/src/utils/framework-delegate.ts

import { ComponentRef, FrameworkDelegate } from '../interface';

export async function attachComponent(delegate: FrameworkDelegate | undefined, container: Element, component: ComponentRef, cssClasses?: string[], componentProps?: {[key: string]: any}): Promise<HTMLElement> {
  if (delegate) {
    return delegate.attachViewToDom(container, component, componentProps, cssClasses);
  }
  if (typeof component !== 'string' && !(component instanceof HTMLElement)) {
    throw new Error('framework delegate is missing');
  }

  const el: any = (typeof component === 'string')
    ? container.ownerDocument.createElement(component)
    : component;

  if (cssClasses) {
    cssClasses.forEach(c => el.classList.add(c));
  }
  if (componentProps) {
    Object.assign(el, componentProps);
  }

  container.appendChild(el);
  if (el.componentOnReady) {
    await el.componentOnReady();
  }
  return el;
}

export function detachComponent(delegate: FrameworkDelegate | undefined, element: HTMLElement | undefined) {
  if (element) {
    if (delegate) {
      const container = element.parentElement;
      return delegate.removeViewFromDom(container, element);
    }
    element.remove();
  }
  return Promise.resolve();
}