react-beautiful-dnd-next/src/state/patch-droppable-map.js

Beautiful and accessible drag and drop for lists with React

// @flow
import type { DroppableDimension, DroppableDimensionMap } from '../types';

export default (
  droppables: DroppableDimensionMap,
  updated: DroppableDimension,
): DroppableDimensionMap => ({
  ...droppables,
  [updated.descriptor.id]: updated,
});