How to filter by object property in angularJS

The documentation has the complete answer. Anyway this is how it is done:

<input type="text" ng-model="filterValue">
<li ng-repeat="i in data | filter:{age:filterValue}:true"> {{i | json }}</li>

will filter only age in data array and true is for exact match.

For deep filtering,

<li ng-repeat="i in data | filter:{$:filterValue}:true"> {{i}}</li>

The $ is a special property for deep filter and the true is for exact match like above.

You simply have to use the filter filter (see the documentation) :

<div id="totalPos">{{(tweets | filter:{polarity:'Positive'}).length}}</div>
<div id="totalNeut">{{(tweets | filter:{polarity:'Neutral'}).length}}</div>
<div id="totalNeg">{{(tweets | filter:{polarity:'Negative'}).length}}</div>

Fiddle