Example
ngRepeat uses $watchCollection to detect changes in the collection. When a change happens, ngRepeat then makes the corresponding changes to the DOM:
- When an item is added, a new instance of the template is added to the DOM.
- When an item is removed, its template instance is removed from the DOM.
- When items are reordered, their respective templates are reordered in the DOM.
Duplicates
track byfor any list that may include duplicate values.track byalso speeds up list changes significantly.- If you don't use
track byin this case, you get the error:[ngRepeat:dupes]
$scope.numbers = ['1','1','2','3','4'];
<ul>
<li ng-repeat="n in numbers track by $index">
{{n}}
</li>
</ul>
