Use RAILS_ENV in runner webpack config.

[phlegx]

This pull request allow to have webpack configs for other environments then development, test and production. For example using environment staging. With this changes an own config/webpack/staging.js is possible (for example with specific process.env variables or webpack configs that differs from production).

Task webpacker:compile has environment production hardcoded. For environments like staging this is not a problem, but for other environments not using a production node environment it is. This could also be changed, respecting the NODE_ENV. Here an example not included in this pull request.

See #1696 #1558 #1274

[gauravtiwari]

Thanks for the PR but I am not sure if there is ever a need of other environments in the context of NODE_ENV. You can use RAILS_ENV to set a custom environment, which will tell webpack to load settings from the relevant section of the webpacker.yml.

As far as webpack is concerned, it will compile, the packs in either production or development mode (with different loaders or plugins useful for that environment). You can supply env variables to change settings during builds. For example, a different API URL for staging vs production.

There is no need for another config file if you are just changing env variables.

[phlegx]

@gauravtiwari you write: You can supply env variables to change settings during builds. For example, a different API URL for staging vs production.

Can you show me please an example how to do that?

[gauravtiwari]

@phlegx Sure, here is some documentation: https://github.com/rails/webpacker/blob/master/docs/env.md

But basically, you can pass env variable like so:

API_URL=foo bundle exec rails s