dojo_app/js/library/dijit/_Container.js

define([
	"dojo/_base/array", // array.forEach array.indexOf
	"dojo/_base/declare", // declare
	"dojo/dom-construct", // domConstruct.place
	"dojo/_base/kernel" // kernel.deprecated
], function(array, declare, domConstruct, kernel){

	// module:
	//		dijit/_Container

	return declare("dijit._Container", null, {
		// summary:
		//		Mixin for widgets that contain HTML and/or a set of widget children.

		buildRendering: function(){
			this.inherited(arguments);
			if(!this.containerNode){
				// All widgets with descendants must set containerNode.
				// NB: this code doesn't quite work right because for TabContainer it runs before
				// _TemplatedMixin::buildRendering(), and thus
				// sets this.containerNode to this.domNode, later to be overridden by the assignment in the template.
				this.containerNode = this.domNode;
			}
		},

		addChild: function(/*dijit/_WidgetBase*/ widget, /*int?*/ insertIndex){
			// summary:
			//		Makes the given widget a child of this widget.
			// description:
			//		Inserts specified child widget's dom node as a child of this widget's
			//		container node, and possibly does other processing (such as layout).

			// I want to just call domConstruct.place(widget.domNode, this.containerNode, insertIndex), but the counting
			// is thrown off by text nodes and comment nodes that show up when constructed by markup.
			// In the future consider stripping those nodes on construction, either in the parser or this widget code.
			var refNode = this.containerNode;
			if(insertIndex > 0){
				// Old-school way to get nth child; dojo.query would be easier but _Container was weened from dojo.query
				// in #10087 to minimize download size.   Not sure if that's still and issue with new smaller dojo/query.
				refNode = refNode.firstChild;
				while(insertIndex > 0){
					if(refNode.nodeType == 1){ insertIndex--; }
					refNode = refNode.nextSibling;
				}
				if(refNode){
					insertIndex = "before";
				}else{
					// to support addChild(child, n-1) where there are n children (should add child at end)
					refNode = this.containerNode;
					insertIndex = "last";
				}
			}

			domConstruct.place(widget.domNode, refNode, insertIndex);

			// If I've been started but the child widget hasn't been started,
			// start it now.  Make sure to do this after widget has been
			// inserted into the DOM tree, so it can see that it's being controlled by me,
			// so it doesn't try to size itself.
			if(this._started && !widget._started){
				widget.startup();
			}
		},

		removeChild: function(/*Widget|int*/ widget){
			// summary:
			//		Removes the passed widget instance from this widget but does
			//		not destroy it.  You can also pass in an integer indicating
			//		the index within the container to remove (ie, removeChild(5) removes the sixth widget).

			if(typeof widget == "number"){
				widget = this.getChildren()[widget];
			}

			if(widget){
				var node = widget.domNode;
				if(node && node.parentNode){
					node.parentNode.removeChild(node); // detach but don't destroy
				}
			}
		},

		hasChildren: function(){
			// summary:
			//		Returns true if widget has child widgets, i.e. if this.containerNode contains widgets.
			return this.getChildren().length > 0;	// Boolean
		},

		_getSiblingOfChild: function(/*dijit/_WidgetBase*/ child, /*int*/ dir){
			// summary:
			//		Get the next or previous widget sibling of child
			// dir:
			//		if 1, get the next sibling
			//		if -1, get the previous sibling
			// tags:
			//		private
			var children = this.getChildren(),
				idx = array.indexOf(children, child);	// int
			return children[idx + dir];
		},

		getIndexOfChild: function(/*dijit/_WidgetBase*/ child){
			// summary:
			//		Gets the index of the child in this container or -1 if not found
			return array.indexOf(this.getChildren(), child);	// int
		}
	});
});