fix: was doubling up on writes to drake.models, causing sometimes wrong model order

fixes #878, hopefully.

Author: cormacrelf

modules/ng2-dragula/src/components/dragula.directive.ts

@@ -12,15 +12,12 @@ export class DragulaDirective implements OnChanges, OnDestroy {
 
   private subs: Subscription;
 
-  private container: any;
+  private get container(): HTMLElement {
+    return this.el && this.el.nativeElement;
+  }
   private group: Group;
 
-  private el: ElementRef;
-  private dragulaService: DragulaService;
-  public constructor(el: ElementRef, dragulaService: DragulaService) {
-    this.el = el;
-    this.dragulaService = dragulaService;
-    this.container = el.nativeElement;
+  public constructor(private el: ElementRef, private dragulaService: DragulaService) {
   }
 
   public ngOnChanges(changes: {dragula?: SimpleChange, dragulaModel?: SimpleChange}): void {

modules/ng2-dragula/src/components/dragula.service.ts

@@ -166,7 +166,6 @@ export class DragulaService {
       let sourceModel = drake.models[drake.containers.indexOf(source)];
       sourceModel = sourceModel.slice(0); // clone it
       const item = sourceModel.splice(dragIndex, 1)[0];
-      drake.models[drake.containers.indexOf(source)] = sourceModel;
       // console.log('REMOVE');
       // console.log(sourceModel);
       this.dispatch$.next({
@@ -196,7 +195,6 @@ export class DragulaService {
         sourceModel = sourceModel.slice(0)
         item = sourceModel.splice(dragIndex, 1)[0];
         sourceModel.splice(dropIndex, 0, item);
-        drake.models[drake.containers.indexOf(source)] = sourceModel;
         // this was true before we cloned and updated sourceModel,
         // but targetModel still has the old value
         targetModel = sourceModel;
@@ -216,8 +214,6 @@ export class DragulaService {
         }
         targetModel = targetModel.slice(0)
         targetModel.splice(dropIndex, 0, item);
-        drake.models[drake.containers.indexOf(source)] = sourceModel;
-        drake.models[drake.containers.indexOf(target)] = targetModel;
         if (isCopying) {
           try {
             target.removeChild(dropElm);