javascript - Angular custom filter and indexOf condition -

i'm new computers , trying build custom filter angularjs app.

i have search string of intergers (cultivos.age) , return item if string contains mes.age condition. i've managed make workingfilter returns == values. can't manage write 'indexof' condition returns item if mes.age contained in cultivos.age array

the working filter:

    angular.module('calendariofilters',[]).filter('filtromes', function(){     return function(cultivos, name){        var arraytoreturn = [];             (var i=0; i<cultivos.length; i++){         if (cultivos[i].age == this.mes.age) {             arraytoreturn.push(cultivos[i]);         }      }     return arraytoreturn; }; 

});

and not working filter:

    angular.module('calendariofilters',[]).filter('filtromes', function(){     return function(cultivos, name){     var arraytoreturn = [];             (var i=0; i<cultivos.length; i++){         if (cultivos[i].age.indexof(this.mes.age) !== -1)  {             arraytoreturn.push(cultivos[i]);         }      }           return arraytoreturn; }; 

});

i'm calling filter in html

     <li ng-repeat="cultivo in cultivos | filtromes:''">       

console logs "typeerror: cannot read property 'length' of undefined" in working filter.

thanks!

change line:

if (item.age.indexof(this.mes.age) >= -1) { 

to:

if (item.age.indexof(this.mes.age) !== -1) { 

hope helps.