How to filter by object property in angularJS

ghz 1years ago ⋅ 2347 views

Question

I am trying to create a custom filter in AngularJS that will filter a list of objects by the values of a specific property. In this case, I want to filter by the "polarity" property(possible values of "Positive", "Neutral", "Negative").

Here is my working code without the filter:

HTML:

<div class="total">
    <h2 id="totalTitle"></h2>
    <div>{{tweets.length}}</div>
    <div id="totalPos">{{tweets.length|posFilter}}</div>
    <div id="totalNeut">{{tweets.length|neutFilter}}</div>
    <div id="totalNeg">{{tweets.length|negFilter}}</div>
</div>

Here is the "$scope.tweets" array in JSON format:

{{created_at: "Date", text: "tweet text", user:{name: "user name", screen_name: "user       screen name", profile_image_url: "profile pic"}, retweet_count: "retweet count", polarity: "Positive"},
 {created_at: "Date", text: "tweet text", user:{name: "user name", screen_name: "user screen name", profile_image_url: "profile pic"}, retweet_count: "retweet count", polarity: "Positive"},
 {created_at: "Date", text: "tweet text", user:{name: "user name", screen_name: "user screen name", profile_image_url: "profile pic"}, retweet_count: "retweet count", polarity: "Positive"}}

The best filter I could come up with as follows:

myAppModule.filter('posFilter', function(){
return function(tweets){
    var polarity;
    var posFilterArray = [];
    angular.forEach(tweets, function(tweet){
        polarity = tweet.polarity;
        console.log(polarity);
        if(polarity==='Positive'){
              posFilterArray.push(tweet);
        }
        //console.log(polarity);
    });
    return posFilterArray;
};
});

This method returns an empty array. And nothing is printed from the "console.log(polarity)" statement. It seems like I am not inserting the correct parameters to access the object property of "polarity."

Any ideas? Your response is greatly appreciated.

Answer

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](http://jsfiddle.net/rAFjL/)

#angularjs