javascript 在 Underscore.js/Backbone.js 模板中使用 IF 语句
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Using IF statements in Underscore.js/Backbone.js templates
提问by Nyxynyx
I am receiving a JSON object where one of the value is null. The JSON looks like:
我收到一个 JSON 对象，其中一个值是null. JSON 看起来像：
[{"id":"1096","price":null,
Right now, it is outputting a NULLstring to the webpage with the following code. (I am using the template engine in Backbone.js/Underscore.js)
现在，它正在NULL使用以下代码将字符串输出到网页。（我在 Backbone.js/Underscore.js 中使用模板引擎）
<div class="subtitle">$<%= price %></div>
Because I want to hide the entire divif no priceis returned, I added the ifstatements:
因为我想隐藏整个divif noprice返回，我添加了if语句：
<% if (price) { %>
<div class="subtitle">$<%= price %></div>
<% } %>
However it seems to still output the div.subtitle. What am I doing wrong? I also tried the following but they did not work
但是它似乎仍然输出div.subtitle. 我究竟做错了什么？我也尝试了以下但他们没有工作
<% if (typeof(price) != "undefined") { %>
<div class="subtitle">$<%= price %></div>
<% } %>
<% if (price != null) { %>
<div class="subtitle">$<%= price %></div>
<% } %>
<% if (price != "null") { %>
<div class="subtitle">$<%= price %></div>
<% } %>
I suspect this has to do with using ifstatements inside Underscore.js's templates
我怀疑这与使用ifUnderscore.js 模板中的语句有关
回答by CaffGeek
Uh, don't you want (no exclamation mark)
呃，你不想要（没有感叹号）
<% if (price) { %>
<div class="subtitle">$<%= price %></div>
<% } %>
Because you are current saying if there is no price then display the price...which makes no sense.
因为你现在说如果没有价格，那么显示价格......这是没有意义的。
回答by Christoph
nullis not undefined!
null不是undefined！
If your json-object is correctly decoded, then checking (price)or (price != null)should be fine.
如果你的 json-object 被正确解码，那么检查(price)or(price != null)应该没问题。
