# Webpacker

## Does Hatchbox support Webpacker & Yarn?

Of course! We install Yarn by default on all application servers so you can use Webpacker out of the box.

Webpacker adds itself to the `assets:precompile` step in Rails so your Webpacker assets will be automatically compiled after the asset pipeline finishes.

#### A common mistake people make is using Webpacker assets inside the asset pipeline.&#x20;

These are two separate pipelines and they do not mix in production. You can mistakenly get this to work in development, but this _will not work_ in production. Any assets used in the asset pipeline must be accessible inside the asset pipeline folders.

### I'm getting an error compiling assets

If you see the following errors, you probably just need to a quick fix to your webpacker install:

`Command "webpack" not found`&#x20;

`"/node_modules/.bin/webpack (Errno::ENOENT)"`

Your app might be missing the yarn binstub. This is required to install node modules before compiling assets. Add the following file to your repo as `bin/yarn`

{% code title="bin/yarn" %}
```
#!/usr/bin/env ruby
APP_ROOT = File.expand_path('..', __dir__)
Dir.chdir(APP_ROOT) do
  begin
    exec "yarnpkg", *ARGV
  rescue Errno::ENOENT
    $stderr.puts "Yarn executable was not detected in the system."
    $stderr.puts "Download Yarn at https://yarnpkg.com/en/docs/install"
    exit 1
  end
end
```
{% endcode %}

`bin/yarn` also needs to be marked as executable in git so that it can be run during the precompile stage.

```
git add --chmod=+x bin/yarn
git commit -m "Add bin/yarn"
git push
```

Then your next deploy should correctly run Yarn to install the packages at the beginning of the assets precompile.
