blocks|key|1062076|text|您很可能在{{if}}子句的命名空间中，因此它的行为有所不同。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1062077|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

You're most likely in the namespace of the {{if}} clause, therefore it behaves differently.

blocks|key|1605771|text|当{{if}子句中的属性名以大写字母开头时，我看到了同样的问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1605772|我认为下面的问题讨论可能是说明https://github.com/emberjs/ember.js/issues/1493的根本原因|offset|length|1605773|sly7-7两年前被评论过
我认为这是因为在工具栏中使用大写名称可以搜索全局。在编写Foo.Bar时，我认为工具栏试图解析名称空间Foo，然后是类或属性栏。|blockquote|1605774|1605775|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/emberjs/ember.js/issues/1493^0|0|F|1B|0|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@$D|T|E|U|1|V]]|A|$]]|$1|F|3|G|5|H|7|W|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|X|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|Q]]]]

I saw the same issue when the property name in the {{if}} clause was starting with a capital letter.

I think the following issue discussion might be stating the root cause <a href="https://github.com/emberjs/ember.js/issues/1493" rel="nofollow">https://github.com/emberjs/ember.js/issues/1493</a>

<blockquote>
 sly7-7 commented 2 years ago
 
 I think this is because using
 Capitalize names in handlebars makes it to search for globals. When
 writing Foo.Bar, I think handlebars is trying to resolve the
 namespace Foo, then a class or property Bar.
</blockquote>

blocks|key|4072880|text|我也看到了同样的错误。根据这个线程的提示，我得出结论，它确实来自于具有大写键名的重调JSON模型。在我的例子中，我返回的JSON如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4072881|{
++++ClassName:+"3rd+Grade+-+Thompson",
++++SubjectID:+"20509",
++++SubjectName:+"English"
}|code-block|syntax|javascript|4072882|在我的Ember路由中，我定义了模型，在下面的代码中运行返回的JSON，以使所有的键值小写：|4072883|App.GradesRoute+=+Ember.Route.extend({
++++model:+function(){
++++++var+url+=+"https://URL-To-JSON-API";
++++++var+grades+=+[];

++++++return+Ember.$.getJSON(url).then(function(data){
++++++++$.each(data,+function(index,+obj){
++++++++++var+grade+=+{};
++++++++++$.each(obj,+function(key,+value){
++++++++++++grade[key.toLowerCase()]+=+value;
++++++++++});
++++++++++grades.push(grade);
++++++++});
++++++++return+grades;
++++++});
++++}
});|4072884|然后，在我的车把代码中，我把我所有的键名都换成了小写，如下所示：|4072885|<script+type="text/x-handlebars"+id="grades">
++{{#each+grade+in+model}}
++++
++++++{{grade.classname}}
++++++++{{#if+grade.subjectid}}
++++++++++{{grade.subjectname}}
++++++++{{/if}}
++++++{{grade.number}}+/+{{grade.letter}}
++++
+{{else}}
+++No+grades+posted
+{{/each}}|4072886|​|4072887|它就像一种魅力。希望这能帮上忙。我知道我花了几个小时想办法解决这个问题，希望我能让别人免于麻烦。|4072888|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|Y|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|10|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|11|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

I too have seen the same error. Following the hints from this thread, I concluded that it was indeed from the retuning JSON model having uppercase key names. In my case, the JSON I was returning looked like this:

<pre><code>{
 ClassName: "3rd Grade - Thompson",
 SubjectID: "20509",
 SubjectName: "English"
}
</code></pre>

This JSON was causing the 'chains is undefined error to appear. In my Ember route, where I defined the model, I ran the returning JSON through the following code to make all key values lowercase:

<pre><code>App.GradesRoute = Ember.Route.extend({
 model: function(){
 var url = "https://URL-To-JSON-API";
 var grades = [];

 return Ember.$.getJSON(url).then(function(data){
 $.each(data, function(index, obj){
 var grade = {};
 $.each(obj, function(key, value){
 grade[key.toLowerCase()] = value;
 });
 grades.push(grade);
 });
 return grades;
 });
 }
});
</code></pre>

Then in my handlebars code I just switched all of my key names to lowercase like so: 

<pre><code>&lt;script type="text/x-handlebars" id="grades"&gt;
 {{#each grade in model}}
 &lt;p&gt;
 {{grade.classname}}
 {{#if grade.subjectid}}
 {{grade.subjectname}}
 {{/if}}
 {{grade.number}} / {{grade.letter}}
 &lt;/p&gt;
 {{else}}
 &lt;p&gt;No grades posted&lt;/p&gt;
 {{/each}}
</code></pre>



And it worked like a charm. Hope this helps someone. I know I spent a good few hours trying to figure this out, hopefully I can spare someone else the trouble.

I have a handlebars template in my Ember app. 

<pre><code>{{#if image}}
 &lt;img src="{{unbound image}}" /&gt;
{{/if}}
</code></pre>

The if statement is working correctly but it seems to be breaking when navigating back tot he homepage. I get this error when I go back to the index route.

<pre><code>TypeError: chains is undefined

ember.js (line 4177)
var chains = this._chains, node = chains[key];
</code></pre>

When I remove the if conditional in my handlebars template. I no longer get the error and I can go back to the homepage with no issues.

I am using Ember JS Beta 1.5.0-beta.2, Handblebars 1.3.0 and jQuery 1.11.0.

It is really strange that the if conditional could break this, but I spent several hours trying to narrow it down and this is what I concluded to be the issue.

"TypeError: chains is undefined " when adding a handlebars if helper and navigating to homepage of app

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我在我的Ember应用程序中有一个车把模板。{{#if image}} <img src="{{unbound image}}" />{{/if}}if语句工作正常，但当导航回主页时，它似乎正在中断。当我回到索引路径时，会得到这个错误。TypeError: chains is undefinedember.js ...

问"TypeError:链是未定义的“当添加一个把手时，如果帮助并导航到应用程序的主页
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