di-correct-way.js

app.controller('MainCtrl', ['$scope', '$timeout', function($scope, $timeout){
    $timeout(function() {
        console.log($scope);
    });
}]);

//another best bractice approach with $inject

app.controller('MainCtrl', mainCtrl);

mainCtrl.$inject = ['$scope', '$timeout'];

function mainCtrl($scope, $timeout) {
     $timeout(function() {
        console.log($scope);
    });
}