When developing an ionic app, sometimes parameters passed through a navController can return a value of Undefined, this is so annoying when you are trying to pass data from one page to another in Ionic Cordova app.
Solution:
Make sure that you are getting the values passed from a navController from the ionViewDidLoad() function, because this function fires after all components or necessary components are loaded, that time the function is firing all data might be loaded already.
[NB] Research about Ionic Page Life Cycle to understand more events in SDL (Software Design Lifecycle)