Webpacker can't find application.js in manifest.json Heroku Production

Question

I'm having a webpacker issue with my app on heroku.

The log:

ActionView::Template::Error (Webpacker can't find application.js in /app/public/packs/manifest.json. Possible causes:
2018-07-04T18:47:08.192729+00:00 app[web.1]: 1. You want to set webpacker.yml value of compile to true for your environment
2018-07-04T18:47:08.192730+00:00 app[web.1]:    unless you are using the `webpack -w` or the webpack-dev-server.
2018-07-04T18:47:08.192733+00:00 app[web.1]: 2. webpack has not yet re-run to reflect updates.
2018-07-04T18:47:08.192734+00:00 app[web.1]: 3. You have misconfigured Webpacker's config/webpacker.yml file.
2018-07-04T18:47:08.192735+00:00 app[web.1]: 4. Your webpack configuration is not creating a manifest.
2018-07-04T18:47:08.192737+00:00 app[web.1]: Your manifest contains:
2018-07-04T18:47:08.192738+00:00 app[web.1]: {
2018-07-04T18:47:08.192740+00:00 app[web.1]: }
2018-07-04T18:47:08.192741+00:00 app[web.1]: ):

I have a manifest.json file which does contain application.js:

{
  "application.css": "/packs/application-c922057d6b9db34084d6e52c6f32baa9.css",
  "application.css.map": "/packs/application-c922057d6b9db34084d6e52c6f32baa9.css.map",
  "application.js": "/packs/application-ab33c1479403810d7775.js",
  "application.js.map": "/packs/application-ab33c1479403810d7775.js.map"
}

It's interesting the final line in the log:

2018-07-04T18:47:08.192737+00:00 app[web.1]: Your manifest contains:
2018-07-04T18:47:08.192738+00:00 app[web.1]: {
2018-07-04T18:47:08.192740+00:00 app[web.1]: }

Is the formatting in the json wrong somehow?

I've tried running bundle exec rails webpacker:compile which was fine, and I've also updated the binstub bundle exec rails webpacker:binstubs, neither seem to have made a difference after pushing to Heroku.

What else can I try?

score 11 · Answer 1 · answered Oct 11 '19 at 11:24

11

I removed folder node_modules
then on terminal yarn add @rails/webpacker@next
then bundle exec rails webpacker:install

after that, it's fixed

answered Oct 11 '19 at 11:24

Hany Moh.

949
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2

I tried many things, really... many things, but this one worked for me – Feber Castellon Feb 08 '20 at 23:29
3

My hero!!! If you're ever in Vancouver I'm taking you out to lunch. – Singh Raman Feb 02 '21 at 07:21
Thank you so much. – cratag Feb 03 '21 at 14:56
Hany you have four lunches waiting for you in Vancouver. It's worth the trip! – duhaime Apr 07 '22 at 12:08

score 2 · Answer 2 · answered Jun 30 '19 at 18:49

2

I had the same issue and spent days trying to solve it. Finally installed webpacker 3.5 and works fine.

It is not the best solution but that gets my app up. I went on a rabbit hole trying solve this issue.

answered Jun 30 '19 at 18:49

gsumk

809
10
15

A year later your response continues to be the valid one unfortunately. I had to update from 3.5 to 4.0 for it to work, after multiple days and several failed attempts to fix this issue. Still no clue what was causing it but works now. – Esteban Bouza Jul 15 '19 at 22:24
what a mess, on webpack 6 now so this is obsolete. funny thing is it's happened before and I've fixed it.. then it happened again(!!). webpack(er) needs removing from the internet. – Damien Roche Mar 29 '21 at 20:17

score 2 · Answer 3 · answered Aug 02 '19 at 07:52

2

bundle exec bin/webpack-dev-server

this command solved my issue. I'm new to webpack, so I don't know how / why.

answered Aug 02 '19 at 07:52

Oshan Wisumperuma

1,808
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6

Running the dev-server on production is not really what you want. – Robin Aug 16 '19 at 08:33

score 0 · Answer 4 · answered Aug 04 '18 at 13:19

0

In case you are still stuck with this, I was having exactly the same problem and no other answers seemed to solve it for me. This GH thread advised ensuring that assets weren't precompiled locally (by removing /public/assets and /public/packs directories, essentially encouraging Heroku to compile for itself. Seems to have cleared up the issue for me for now.

https://github.com/rails/webpacker/issues/532

answered Aug 04 '18 at 13:19

André Goldstein

367
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If you do that, precompiling assets would be failed and it won't be deployed on Heroku. – Aboozar Rajabi Jun 12 '19 at 16:43

score 0 · Answer 5 · answered Sep 28 '20 at 21:20

I ran into the exact same error. Try this if you have not yet.

run bundle exec rails webpacker:install

check console logs for the error message

The engine "node" is incompatible with this module. Expected version ">= 10.13.0". Got "10.0.0"
error Found incompatible module.

if yes, then you can resolve this issue in 3 steps:

$ node -v checks your node version

$ nvm install 'required node version' changes the node version

$ bundle exec rails webpacker:install It will validate your package.json, resolve and fetch all the packages, link and save dependencies

score 0 · Answer 6 · answered Nov 23 '20 at 17:12

0

In my case below steps helped for newly added pack file that was not found by webpacker

RAILS_ENV=staging rake  assets:clean

rake assets:clobber

RAILS_ENV=production rake assets:precompile

answered Nov 23 '20 at 17:12

Syed Shibli

992
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Webpacker can't find application.js in manifest.json Heroku Production

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