Try change condition ng-click, if lenght > 1 is clickable, esle not.
ng-click="filtered.length >1 ? 'false' : 'true' || showSomething($index)"
What is wrong?
you could do that
<a ng-click="1==1 ? test() : null">click</a>
There is also ng-disabled, which may be helpful. https://docs.angularjs.org/api/ng/directive/ngDisabled
<div data-ng-click="showSomething($index)" data-ng-disabled="filtered.length <=1"></div>
Please note though, that this does change the look/feel of the button (ie. disabled button).