尝试在js.erb文件中使用控制器变量时抛出NoMethodError [英] NoMethodError thrown when trying to use controller variables in js.erb file

问题描述

在我的资产中，我有一个名为 maps.js.erb 的文件，基本上只有以下（调试）内容：

In my assets, I have a file called maps.js.erb, basically with only the following (debugging) content:

alert("<%= @map.width %>");

这个JS文件是通过 show.html.erb 属于地图的视图。

This JS file is loaded through the show.html.erb view belonging to maps.

<%= javascript_include_tag params[:controller] %>
<h1><%= @map.title %></h1>
…

HTML文件本身显示地图的标题，例如：浏览 / maps / 1 / 时，由于 @map 在控制器中定义。但是，只要我包含JS文件，就会出现以下错误：

The HTML file itself shows the map's title, e.g. when browsing to /maps/1/, since @map is defined in the controller. However, as soon as I include the JS file, I get the following error:

地图中的NoMethodError＃show

显示 ... / app / views / maps / show.html.erb 第1行引发的地方：

NoMethodError in Maps#show

Showing …/app/views/maps/show.html.erb where line #1 raised:

nil的未定义方法'title'：NilClass
（在 ... / app / assets / javascripts / maps.js.erb ）

undefined method 'title' for nil:NilClass (in …/app/assets/javascripts/maps.js.erb)

• 为什么 @map 在 js.erb 档案？


• 我还能如何访问我的控制器中定义的这个实例变量？


• Why is @map not available in the js.erb file?
• How else can I access this instance variable defined in my controller?

推荐答案

Ryan Bates就该主题做了一个截屏视频 - 你可能想看一下：

Ryan Bates did a screencast right on that topic - you might wanna check it out:

http://railscasts.com/episodes/324-passing-data-to-javascript

在 html.erb 文件中，您可以定义变量：

In the html.erb file, you can define the variables:

<%= javascript_tag do %>
  window.productsURL = "<%=j products_url %>";
  window.products = <%=raw Product.limit(10).to_json %>;
<% end %>

这篇关于尝试在js.erb文件中使用控制器变量时抛出NoMethodError的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！