I'm new to webpacker and yarn. I installed successfully the package with:

yarn add moment

EDIT2:

This is my import

# app/javascript/packs/application.js
import moment from 'moment/moment'
import 'moment/locale/de-ch'

Problem: I can't use the "moment" package in my old JS asset files

First works, the other not:

# in: app/javascript/packs/application.js
console.log('Log: ' + moment([2007, 0, 29]).toNow()) #=> Log: in 10 Jahren

# in app/*assets*/javascripts/application.js
console.log('Log2: ' + moment([2007, 0, 29]).toNow()) #=> Uncaught ReferenceError: moment is not defined

EDIT1:

Here the key points of the installation process of webpacker:

1. in gemfile: gem 'webpacker', github: 'rails/webpacker'
2. Add this line to assets.rb: Rails.application.config.assets.paths << Rails.root.join('node_modules')
3. Add in %head of application.html.haml this: = javascript_pack_tag 'application'
4. Restart Rails server and start webpacker

Note: I upgraded my app from Rails 4.2 to 5.0 and later to 5.1; maybe something is missing in my app

I'm new to webpacker and yarn. I installed successfully the package with:

yarn add moment

EDIT2:

This is my import

# app/javascript/packs/application.js
import moment from 'moment/moment'
import 'moment/locale/de-ch'

Problem: I can't use the "moment" package in my old JS asset files

First works, the other not:

# in: app/javascript/packs/application.js
console.log('Log: ' + moment([2007, 0, 29]).toNow()) #=> Log: in 10 Jahren

# in app/*assets*/javascripts/application.js
console.log('Log2: ' + moment([2007, 0, 29]).toNow()) #=> Uncaught ReferenceError: moment is not defined

EDIT1:

Here the key points of the installation process of webpacker:

1. in gemfile: gem 'webpacker', github: 'rails/webpacker'
2. Add this line to assets.rb: Rails.application.config.assets.paths << Rails.root.join('node_modules')
3. Add in %head of application.html.haml this: = javascript_pack_tag 'application'
4. Restart Rails server and start webpacker

Note: I upgraded my app from Rails 4.2 to 5.0 and later to 5.1; maybe something is missing in my app

• javascript
• ruby-on-rails
• webpacker

• I use moment.js in a regular asset JS-file: app/assets/javascript/<my_file>.coffee – Pascal Commented Jul 26, 2017 at 21:17
• Did you try import { moment } from 'moment/moment'? – Sebastián Palma Commented Jul 26, 2017 at 21:19
• @palma I did now; still the error – Pascal Commented Jul 26, 2017 at 21:23
• Do I have to include the old "asset"-tree to webpacker? I installed webpacker today and it's not an new rails app – Pascal Commented Jul 26, 2017 at 21:25
• Can you import any other ponent, library? How are you testing the import of moment, I've tried your second way and it works. – Sebastián Palma Commented Jul 26, 2017 at 21:30

2 Answers 2

I has a similar issue that momentjs was being used throughout the app/assets/javascript files and it was included via gem (actually, even worse, rails-assets). Looks like we both needed moment object to be available globally, not just inside the pack. So, the following fixed that for me and I'll keep it around until I get rid of app/assets/javascript files.

import moment from 'moment'

window.moment = moment

First I thought this is a solution, but it's not: https://github./rails/webpacker#resolved-paths

In "/config/webpacker.yml" I added this:

# /config/webpacker.yml    
resolved_paths: ['app/assets']

An here I imported the files that use "moment.js":

# /app/javascript/packs/application.js
import 'javascripts/<folder>/<some_file_uses_moment>.coffee'

=> Still the error

Later I fount this article: http://samuelmullen./articles/embracing-change-rails51-adopts-yarn-webpack-and-the-js-ecosystem/

What happened to the Asset Pipeline? Long story short: nothing. You can still use the asset pipeline the way you always have – ”If you like your asset pipeline, you can keep your asset pipeline”. That includes the javascripts/ directory. You can even mix packaged files with “pipelined” files in your views. You just can’t include your packaged files into your “pipelined” files; well, not easily.

It seems I can't mix the "moment" package with "old" asset JS (?)