Wrapping react-beautiful-dnd components so that we can pass `onDragEnd` directly to each `Droppable`

wrapped-react-beautiful-dnd.js

import {
  DragDropContext as RealDragDropContext,
  Droppable as RealDroppable,
  Draggable
} from 'react-beautiful-dnd';
import React, { Component } from 'react';


const DroppableManager = {
  _onDragEndLookup: {},

  register(droppableId, onDragEnd) {
    assert(!(droppableId in this._onDragEndLookup),
      `droppableId="${droppableId}" has already been used. droppableIds should be unique.`);
    this._onDragEndLookup[droppableId] = onDragEnd;
  },

  unregister(droppableId) {
    delete this._onDragEndLookup[droppableId];
  },

  getOnDragEnd(droppableId) {
    return this._onDragEndLookup[droppableId]
  }
};


class Droppable extends Component {
  componentDidMount() {
    const { droppableId, onDragEnd } = this.props;
    assert(onDragEnd,
      `Droppable with droppableId="${droppableId}"" is missing 'onDragEnd' hook.`);
    DroppableManager.register(droppableId, onDragEnd);
  }

  componentWillUnmount() {
    const { droppableId } = this.props;
    DroppableManager.unregister(droppableId);
  }

  render() {
    const { children, ...otherProps } = this.props;
    return (
      <RealDroppable {...otherProps}>
        {children}
      </RealDroppable>
    );
  }
}


class DragDropContext extends Component {
  globalOnDragEnd = (result)=> {
    const { type, source, destination } = result;
    if (!destination) { return; }
    if (source.droppableId === destination.droppableId && source.index === destination.index) {
      return;
    }
    const onDragEnd = DroppableManager.getOnDragEnd(destination.droppableId);
    onDragEnd(result);

    if (this.props.onDragEnd) {
      this.props.onDragEnd(result);
    }
  };

  render() {
    return (
      <RealDragDropContext onDragEnd={this.globalOnDragEnd}>
        {this.props.children}
      </RealDragDropContext>
    );
  }
}

export { Droppable, DragDropContext, Draggable };


// ---------------------------------------------

function assert(condition, message) {
  if (!condition) {
    throw new Error(message || 'Assertion failed');
  }
};