How to use javascript_include_tag to get all scripts in a folder ruby on rails

Since the file exist inside assets/javascript you can add in application.html.erb as follows:

<%= javascript_include_tag "ntc" %>
# => <script src="/assets/ntc.js"></script>

if you want to specify from other folder path then u can use as below:

<%= javascript_include_tag "xmlhr", host: "localhost", protocol: "https" %>
# => <script src="https://localhost/assets/xmlhr.debug-1284139606.js"></script>

As @Max mentioned, you can use asset pipeline to include controller specific stylesheets and JavaScript files only in their respective controllers.

If you have a folder of script files and want to load all for a particular controller for example:

assets
| 
|___ javascript
        |
        |___ ntc.js
        |
        |___ ntc
              |__script1.js
              |__script2.js

Then you can require these files inside ntc.js as follows:

 //= require ntc/script1
 //= require ntc/script2

And can use

<%= javascript_include_tag params[:controller] %>

for more information refer this documentation