Getting undefined method `javascript_pack_tag' for ...

[schovi]

Having Rails 5 application and followed this tutorial https://medium.com/statuscode/introducing-webpacker-7136d66cddfb#.4xpiogt9l how to install and run webpacker.

Having webpacker in Gemfile

gem 'webpacker', github: 'rails/webpacker'

And used installation commands

rails webpacker:install
rails webpacker:install:react

And when open page with <%= javascript_pack_tag 'app' %> I am getting undefined method 'javascript_pack_tag' for #<#<Class:0x007f8d5a158378>:0x007f8d5a0015b0>

./bin/webpack-dev-server runs fine (but having some babel errors, but I guess that can't have impact on previous error).

[ytbryan]

It works on my side. I'm using rails 5.1.0.beta1, latest webpacker from github.

Did you bundle install?

Not sure what error you got for webpack-dev-server, but if your port is blocked, you will encounter error like [Error] Failed to load resource: the server responded with a status of 404 (File Not Found) (hello_react.js, line 0). The solution is to edit development.rb and change the port from 8080 to something else (ie 8081)

Let me know if the problem is resolved.

[schovi]

@ytbryan Sure I run bundle install

Using webpacker 1.0 from git://github.com/rails/webpacker.git (at master@a85a3ab)

Tutorial said it is for Rails 4.2+ and unfortunately due to dependency hell in my project I can't update to 5.1 yet :(

[schovi]

I traced the gem source code webpacker/lib/webpacker/railitie.rb

class Webpacker::Engine < ::Rails::Engine
  initializer :webpacker do |app|
    p "Initializing webpacker"
    ActiveSupport.on_load :action_controller do
      p "Using Webpacker::Helper"
      ActionController::Base.helper Webpacker::Helper
    end

and it printed my debug, but still same error.

Then I tried to use Helper manually and everything is fine.

class ApplicationController < ActionController::Base
  helper Webpacker::Helper
end

[ytbryan]

May I know which rails version is this project on?

[schovi]

@ytbryan Rails 5.0.1

[ytbryan]

Just tested it with 5.0.1 and it still works fine on my end.

[schovi]

Maybe some conflict gem?

[ytbryan]

I don't have enough info to confirm that.

Can you close this if the manual helped fixes it? Feel free to open it again if you find the root of the problem.

[schovi]

Thanks

[gauravtiwari]

@schovi Were you using .js.erb extension for app pack?

[gauravtiwari]

If yes to above, do you got javascript comments in that file? Please remove that since it's erb. I have made a demo for you here - https://tranquil-inlet-61365.herokuapp.com/ and code is here - https://github.com/gauravtiwari/webpacker-demo-app

[schovi]

@gauravtiwari I have bare structure generated by rails webpacker:install and rails webpacker:install:react nothing more.
And I think problem is strictly related to Rails and its Helpers, because of manaully using

class ApplicationController < ActionController::Base
  helper Webpacker::Helper
end

works fine.

[gauravtiwari]

Ah right, but it's bit strange too, given you are using Rails 5.0.1. It works without including helper for me - https://github.com/gauravtiwari/webpacker-demo-app. Perhaps, application.rb is setup differently - I mean includes on the top that adds gems from Rails?

[schovi]

@guilleiguaran

require_relative 'boot'

require 'active_record/railtie'
require 'action_controller/railtie'
require 'action_view/railtie'
# require 'action_mailer/railtie'
# require 'action_cable/engine'
# require 'rails/test_unit/railtie'
require 'sprockets/railtie'
require 'sidekiq/api'

# Require the gems listed in Gemfile, including any gems
# you've limited to :test, :development, or :production.
Bundler.require(*Rails.groups)

module MyApp
...