使用ng-if与值或函数有什么区别吗？

ng-if="myvalue"
ng-if="myfunc()"

更新（为了更好地理解我为什么要）

html

<div class="navbar navbar-default navbar-static-top" data-ng-controller="NavController as nav">
            <div class="container">
                <ul class="nav navbar-nav">
                    <a data-ui-sref="home" class="navbar-brand"><i class="logo"></i> Angular Express</a>
                    <li ui-sref-active="active"><a data-ui-sref="home">Home</a></li>
                </ul>
                <ul class="nav navbar-nav navbar-right" data-ng-if="!nav.isAuthenticated()">
                    <li><a data-ui-sref="session.login">Log in</a></li>
                    <li><a data-ui-sref="session.signup">Sign up</a></li>
                </ul>
                <ul class="nav navbar-nav navbar-right" data-ng-if="nav.isAuthenticated()">
                    <li><i class="fa fa-user"></i> <span ng-bind="nav.isAuthenticated().username"></span> <a href="/api/auth/logout" data-ng-click="nav.logout()">Logout</a></li>
                </ul>
            </div>
        </div>

js

function NavController($rootScope, UserStorage){
    var nav = this;
    nav.isAuthenticated = function() {
        UserStorage.get();
    }; 
}
function UserLoginController($rootScope,$state, Users, UserStorage) {
    var user = this;
    user.data = {};
        user.save = function() {
            Users.login(user.data).then(function(response) {
            console.log(response.data);
            UserStorage.set(response.data);
            $state.go('home');
        })
        .catch(function(response) {
            console.log(response);
            user.errors = response.data;
        });
    };
}

如果我这样使用，我已经达到了$ digest（）迭代

重新更新

（对于chandermani评论）

function UserStorage($sessionStorage) {
  return {
    set: function(data) {
        $sessionStorage.user = angular.toJson(data);
    },
    get: function() {
        return angular.fromJson($sessionStorage.user); 
    },
    del: function() {
        delete $sessionStorage.user;
    }
  };
}