Action view::template::error (Unexpected token: operator (<))

Question

im getting a problem with my deploy at heroku! I just created an app Test with cedar stack, push my app and I have this problem (log)

←[32m2012-03-24T15:10:56+00:00 app[web.1]:←[0m ActionView::Template::Error (Unexpected token: operator (<)
←[32m2012-03-24T15:10:56+00:00 app[web.1]:←[0m   (in /app/app/assets/javascripts/application.js)):
←[32m2012-03-24T15:10:56+00:00 app[web.1]:←[0m     3: <head>
←[32m2012-03-24T15:10:56+00:00 app[web.1]:←[0m     4:   <title>Test</title>
←[32m2012-03-24T15:10:56+00:00 app[web.1]:←[0m     5:   <%= stylesheet_link_tag    "application" %>
←[32m2012-03-24T15:10:56+00:00 app[web.1]:←[0m     6:   <%= javascript_include_tag "application" %>
←[32m2012-03-24T15:10:56+00:00 app[web.1]:←[0m     7:   <%= csrf_meta_tags %>
←[32m2012-03-24T15:10:56+00:00 app[web.1]:←[0m     8: </head>
←[32m2012-03-24T15:10:56+00:00 app[web.1]:←[0m     9: <body>

Any Idea??

Update:

My application.js file

// This is a manifest file that'll be compiled into including all the files listed below.
// Add new JavaScript/Coffee code in separate files in this directory and they'll automatically
// be included in the compiled file accessible from http://example.com/assets/application.js
// It's not advisable to add code directly here, but if you do, it'll appear at the bottom of the
// the compiled file.
//
//= require jquery
//= require jquery_ujs
//= require jquery-ui
//= require_tree .

Does it work properly *in production mode* (with assets precompiled) on your local machine? Do you have any non-js/coffee files under the /app/assets/javascript directory? — pjumble, Mar 24 '12 at 18:08
Probably something funky going on in `application.js`. Have you checked that it works properly in localhost? — Benjamin Tan Wei Hao, Mar 24 '12 at 16:15
No, only application.js and all .js.coffee files generated by rails — Agustin Seifert, Mar 24 '12 at 18:51
Did you have any luck in resolving this? I'm having the same error... — jvillian, Jun 28 '12 at 20:53
Try removing `//= require` lines one-by-one to see which one is causing the error. What other JS/CS files are included with the `require_tree .` call? — Ross Allen, Oct 17 '12 at 05:55

score 1 · Answer 1 · answered Nov 16 '17 at 03:14

1

I ran into this error and it took a while to figure out which file referenced in the manifest was the culprit. Once I figured out which file was causing the error, searching for '>' pulled up several lines but I got lucky and quickly zeroed in a map function which used the => operator:

.map(x => x.id);

Once I changed that to an anonymous function:

.map(function(x) { return x.id; });

the error went away.

answered Nov 16 '17 at 03:14

Chip Roberson

532
3
12

But how to make rails supports ES7? – Abdennour TOUMI Nov 08 '18 at 10:40

score 0 · Answer 2 · answered Dec 15 '12 at 17:14

I've just run into this problem, and the trick was that there was a remaining line of a conflict between the server and my localhost. In my localhost everything seamed fine, but i think that's because of some cache, or something. Anyway, i opened the application.js and remove the lines with the << HEAD...

I let it here for register of the problem and a possible solution

score 0 · Answer 3 · answered Feb 12 '19 at 15:19

NOTE: it's been almost 7 years since the OP asked this question. The issue I experienced is likely a newer problem (with the same error log output as OP). The below answer likely doesn't apply to the issue the OP experienced, but could be helpful to new visitors looking for a solution. My Rails version: 5.1.2

Found the problem

It was an issue with how Production handles my assets.precompile (in config/initializers/assets.rb)

After trial-and-error to find the culprit (a new JS file I created a week ago), I noticed the error vanished after commenting out the line that includes the file in config/initializers/assets.rb.

# Commented out until precompile fix found
# Rails.application.config.assets.precompile += %w( break_the_project.js )

THE FIX

Since this only happened in Production for me, I updated config/environments/production.rb, replacing the line:

config.assets.js_compressor = :uglifier

to:

config.assets.js_compressor = Uglifier.new(harmony: true)

After restarting the Rails server, my World was peaceful once again.

Source

Action view::template::error (Unexpected token: operator (<))

3 Answers3

Found the problem

THE FIX