How to use the dnd-core.DragDropManager function in dnd-core

const getDndContext = () => {
  if (defaultManager) return defaultManager
  defaultManager = new DragDropManager(HTML5Backend)

  return defaultManager
}

var createChildContext = exports.createChildContext = function createChildContext(backend, context) {
	return {
		dragDropManager: new _dndCore.DragDropManager(backend, context)
	};
};

Object.keys(backendFactories).forEach(function (key) {
    childContextTypes[key] = _React$Component$PropTypes.PropTypes.object.isRequired;
    childContext[key] = new _DragDropManager.DragDropManager(backendFactories[key]);
  });

  return zone.runOutsideAngular(() => new DragDropManager(unpackBackendForEs5Users(backend), context))
}

provide () {
    return {
      dragDropManager: new DragDropManager(this.getBackend(), {
        window: this.getWindow()
      })
    }
  },
  methods: {

export default (): DragDropManager => {
  if (defaultManager) {
    return defaultManager
  }

  defaultManager = new DragDropManager(HTML5Backend)
  return defaultManager
}

export default function DragDropContext (backendOrModule, context = {}) {
  let backend = backendOrModule
  if (typeof backend === 'object' && typeof backend.default === 'function') {
    backend = backend.default
  }

  return {
    provide: {
      dragDropManager: new DragDropManager(backend, context)
    }
  }
}

export default function getDragDropManager() {
  if (!defaultManager) {
    defaultManager = new DragDropManager(HTML5Backend);
  }
  return defaultManager;
}