调用初始化函数时无法识别$ scope变量

Question

I have the following code, where I want to receive all the texts from the current user and show them on screen when the page loads:

angular.module('eddieApp')
    .controller('MainController', function ($scope, Principal, TextService) {

        $scope.texts = [];

        Principal.identity().then(function(account) {
            $scope.account = account;
            $scope.isAuthenticated = Principal.isAuthenticated;
        });

        $scope.findByUser = function(){
            TextService.findByUser($scope.account.login).success(function(data){
                $scope.texts = data;
            });
        };

        // receive all notes from current user
        $scope.$watch(function(scope) { return scope.account; },
                      function()      { $scope.findByUser(); });


    });

The problems is that it works, but I don't understand why is this the only method to make it work.

I tried to call the function $scope.findByUser() like this:

angular.module('eddieApp')
    .controller('MainController', function ($scope, Principal, TextService) {

    $scope.texts = [];

    Principal.identity().then(function(account) {
        $scope.account = account;
        $scope.isAuthenticated = Principal.isAuthenticated;
    });

    $scope.findByUser = function(){
        TextService.findByUser($scope.account.login).success(function(data){
            $scope.texts = data;
        });
    };

    $scope.findByUser();

});

but I get an error saying that $scope.account.login isn't recognized.

Also, I tried to put the directive ng-init="findByUser()" in my html code, but again, I get the same error saying that $scope.account.login isn't recognized.

Finally i made it work with the $watch function, but I don't understand why the first two methods didn't work, because they are easier to understand and I would preffer using them instead of $watch .

Answer 1

It works because your $watch ensures that $scope.account is defined before running $scope.findByUser .

In your example without the watch, findByUser executes immediately, and tries to use the login property of $scope.account which is undefined.

If having a user account is a prerequisite of findByUser , and there's nothing in your view that calls it immediately, it may make more sense to call findByUser in your then block, which would avoid the need for a $watch .