AngularJS: Restangular controller single quote issue

I'm using restangular to call external API. The GET request works only if I remove the single quotes from controller. Although, when I try to add an angular chart that fails, unless I add quotes back. So, one or the other works depending on if added or not. I need both to work so can use data from API for chart. Additionally, I'm not seeing any errors in browsers with or without the quotes.

This is partial app.js

var app = angular.module('mymod', ['ngRoute', 'ngResource', 'ui.bootstrap', 'chart.js', 'restangular'])
      .config(function($routeProvider, RestangularProvider) {
          $routeProvider
              .when('/', {
                  templateUrl: 'app/main/main.html',
                  controller: MainCtrl // <--- This is what I'm referring to
              })
              .otherwise({
                  redirectTo: '/'
              });

          // Set base url
          RestangularProvider.setBaseUrl('https://something.com/api/v1');
          // Auth details
          RestangularProvider.setDefaultHeaders({
              'Authorization': 'Token token=mytoken',
              'Content-Type': 'application/json',
          });
          // Format    
          RestangularProvider.setRequestSuffix('.json');
          // Data extractor
          RestangularProvider.setResponseExtractor(function(response, operation) {
              return response.incidents;
          });
      });

  // Graph Example
  app.controller('MainCtrl', function($scope) {
      $scope.labels = ["Download Sales", "In-Store Sales", "Mail-Order Sales"];
      $scope.data = [300, 500, 100];
  });

I added 'use strict'; to top of app.js and am now seeing this error: ReferenceError: i is not defined.
Which references the i in for loop below.

$scope.update = function(pages) {
for (i = 0; i < pages; i++) {
  Restangular.all("incidents").getList({offset:25 * i, sort_by: "created_on:desc"})
    .then(function(result) {
    Array.prototype.push.apply($scope.incidents,result);
    })
}
};

Also, I've been utilizing code example noted below and found a couple problems with it that i've fixed, but I'm new to Angular, so it's been difficult. reference: code example