title: Handle common variables inside the controller
body: <p>I am very new to Salesforce. I am using some variables which is common in multuple methods inside this controller. Is there a way to define the variables once and reuse them inside this component methods?</p>
  <p><strong>controller</strong></p>
  <pre><code>doInit : function(cmp, event, helper) {
     var categoryUsed = 'Abc';
     var locations = ['ten', 'twenty', 'thirty'];
     var address = window.location.search;
     //other logic1
  },
  handleFlag : function(cmp, event, helper) {
     var categoryUsed = 'Abc';
     var locations = ['ten', 'twenty', 'thirty'];
     var address = window.location.search;
     //other logic2
  },
  handleArea : function(cmp, event, helper) {
     var categoryUsed = 'Abc';
     var locations = ['ten', 'twenty', 'thirty'];
     var address = window.location.search;
     //other logic3
  }
  </code></pre>
  <p>Is there a way to declare these common variables (categoryUsed, locations,address) once and use in all the above methods inside this component?</p>