ngRepeat不循环数组

Question

我有这个对象：

{
    "_id" : ObjectId("5454e173cf8472d44e7df161"),
    "questionType" : 0,
    "question" : "question1",
    "answers" : [ 
        {
            "content" : "answer1"
        }, 
        {
            "is_true" : "true",
            "content" : "answer2"
        }, 
        {
            "content" : "answer3"
        }
    ],
    "matches" : [],
    "__v" : 0
}

这个控制器：

var questionIndexController = function ($scope, Question, $routeParams) {
    var question = Question.get({id: $routeParams.id});
    $scope.question = question;
};


angular.module("adminMain")
    .controller("questionIndexController", ["$scope", "Question", "$routeParams", questionIndexController]);

这个标记：

<h3>Question:</h3>
<p>{{ question.question }}</p>
<ul>
    <li np-repeat="answer in question.answers">
        <span ng-show="answer.is_true">✓</span>
        <span>{{ answer.content }}</span>
    </li>
</ul>

但遗憾的是，生成的html并未包含JSON的任何答案。这意味着ngRepeat没有循环遍历question.answers数组。

<div ng-view="" class="ng-scope"><h3 class="ng-scope">Question:</h3>
<p class="ng-binding ng-scope">question1</p>
<ul class="ng-scope">
    <li np-repeat="answer in question.answers">
        <span ng-show="answer.is_true" class="ng-hide">✓</span>
        <span class="ng-binding"></span>
    </li>
</ul>
</div>

知道如何解决这个问题吗？

---

修改

这是问题工厂代码：

var questionFactory = function($resource, restUrls) {
    return $resource(restUrls.question.index, {}, {
        save: {
            url: restUrls.question.add,
            method: "POST",
            isArray: false
        }
    });
};

angular.module("adminMain").factory("Question", ["$resource", "restUrls", questionFactory]);

其中restUrls.question.index为"/api/questions/:id"

node.js用于获取单个问题的后端代码：

function indexQuestions(req, res, next) {
    var questionId = req.params.id || null;
    if(!questionId) next(errorHandler(404, "Not found"));
    Question.findOne({ _id: questionId }, function(err, question) {
        if(err) return next(err);
        if(question.length === 0) return next(errorHandler(404, "Question not found"));
        res.json(question);
    });
}

当console.log(question)从$resource方法返回时，我得到一个普通的promise对象：

Answer 1

有一个拼写错误：

<h3>Question:</h3>
<p>{{ question.question }}</p>
<ul>
    <li np-repeat="answer in question.answers">
        <span ng-show="answer.is_true">✓</span>
        <span>{{ answer.content }}</span>
    </li>
</ul>

应该有ng-repeat而不是np-repeate。