angularjs - using defer in typescript -

i having issues using $q.defer in typescript controller. error this.$q.defer not function. typescript....

export class accountwizardcontroller implements iaccountwizardscope {    account: account;    static $inject = ['$q']   constructor(private $q: ng.iqservice) {   }    savestate(): ng.ipromise<account> {     console.log(this.$q);     var deferred = this.$q.defer<account>();     console.log(deferred);     return deferred.promise;   } }  export interface iaccountwizardscope {   account: contractmonitor.models.account;   savestate(): ng.ipromise<account>; } 

when call savestate() method in view error. has me baffled.

thanks.

$q has had defer since (ref). guess this.$q undefined, , case because have wrong this. fix, use fat arrow preserve context:

savestate = (): ng.ipromise<account> => {     console.log(this.$q);     var deferred = this.$q.defer<account>();     console.log(deferred);     return deferred.promise; }