added support for jQuery sortable's "over" event

README.md

@@ -49,6 +49,16 @@ Note: The sortable binding assumes that the child "templates" have a single cont
 
  This option can be passed in the binding or configured globally by setting `ko.bindingHandlers.sortable.afterMove`. This callback also receives the `event` and `ui` objects as the second and third arguments.
 
+* **hovering** - specify a function to execute while an item is being dragged over a potential location. This function receives an object for its first argument that contains the following information:
+ * `arg.item` - the actual item being moved
+ * `arg.sourceIndex` - the position of the item in the original observableArray
+ * `arg.sourceParent` - the original observableArray
+ * `arg.sourceParentNode` - the container node of the original list. Useful if moving items between lists, but within a single array. The value of `this` in the callback will be the target container node.
+ * `arg.targetIndex` - the targeted position of the item in the destination observableArray
+ * `arg.targetParent` - the destination observableArray
+
+ This option can be passed in the binding or configured globally by setting `ko.bindingHandlers.sortable.afterMove`. This callback also receives the `event` and `ui` objects as the second and third arguments. Warning: this callback might be called multiple times for the same target location.
+
 * **dragged** - specify a function to execute after a draggable item has been dropped into a sortable. This callback receives the drag item as the first argument, the `event` as the second argument, and the `ui` object as the third argument. If the function returns a value, then it will be used as item that is dropped into the sortable. This can be used as an alternative to the original item including a `clone` function.
 
 * **isEnabled** - specify whether the sortable widget should be enabled. If this is an observable, then it will enable/disable the widget when the observable's value changes. This option can be passed in the binding or configured globally by setting `ko.bindingHandlers.sortable.isEnabled`.

build/knockout-sortable.js

@@ -138,6 +138,31 @@
  startActual.apply(this, arguments);
  }
  },
+ over: function(event, ui) {
+ if(!sortable.hovering)
+ return;
+ var sourceParent, targetParent, sourceIndex, targetIndex, arg,
+ el = ui.item[0],
+ placeHolderEl = ui.placeholder[0],
+ item = dataGet(el, ITEMKEY) || dragItem;
+
+ sourceParent = dataGet(el, PARENTKEY);
+ sourceIndex = dataGet(el, INDEXKEY);
+ targetParent = dataGet(placeHolderEl.parentNode, LISTKEY);
+ targetIndex = ko.utils.arrayIndexOf(ui.placeholder.parent().children(), placeHolderEl);
+ if (sourceParent === targetParent && targetIndex > sourceIndex)
+ targetIndex--;
+
+ arg = {
+ item: item,
+ sourceParent: sourceParent,
+ sourceParentNode: sourceParent && ui.sender || el.parentNode,
+ sourceIndex: sourceIndex,
+ targetParent: targetParent,
+ targetIndex: targetIndex
+ };
+ sortable.hovering.call(this, arg, event, ui);
+ },
  receive: function(event, ui) {
  dragItem = dataGet(ui.item[0], DRAGKEY);
  if (dragItem) {
@@ -274,6 +299,7 @@
  allowDrop: true,
  afterMove: null,
  beforeMove: null,
+ hovering: null,
  options: {}
  };
 

src/knockout-sortable.js

@@ -137,6 +137,31 @@
  startActual.apply(this, arguments);
  }
  },
+ over: function(event, ui) {
+ if(!sortable.hovering)
+ return;
+ var sourceParent, targetParent, sourceIndex, targetIndex, arg,
+ el = ui.item[0],
+ placeHolderEl = ui.placeholder[0],
+ item = dataGet(el, ITEMKEY) || dragItem;
+
+ sourceParent = dataGet(el, PARENTKEY);
+ sourceIndex = dataGet(el, INDEXKEY);
+ targetParent = dataGet(placeHolderEl.parentNode, LISTKEY);
+ targetIndex = ko.utils.arrayIndexOf(ui.placeholder.parent().children(), placeHolderEl);
+ if (sourceParent === targetParent && targetIndex > sourceIndex)
+ targetIndex--;
+
+ arg = {
+ item: item,
+ sourceParent: sourceParent,
+ sourceParentNode: sourceParent && ui.sender || el.parentNode,
+ sourceIndex: sourceIndex,
+ targetParent: targetParent,
+ targetIndex: targetIndex
+ };
+ sortable.hovering.call(this, arg, event, ui);
+ },
  receive: function(event, ui) {
  dragItem = dataGet(ui.item[0], DRAGKEY);
  if (dragItem) {
@@ -273,6 +298,7 @@
  allowDrop: true,
  afterMove: null,
  beforeMove: null,
+ hovering: null,
  options: {}
  };