What problem does it solve

It only helps to have better Docker images for better CI/CD.

Let's imagine you want to build a Docker image and deploy it to two different environments: qa-env and staging-env. You don't want to build Nuxt twice for that (because of security, integrity, CI-performance, etc.), so Docker image should already have buildDir (.nuxt) inside. The thing is, almost all environmental variables you pass to such image on docker run, won't be applied, since they already hardcoded by Webpack into nuxt bundle. You only need to install this module to solve this issue.

Why other solutions don't work

If you make a research, there are basically three solutions:

1. Use Vuex to store the variables. Or use nuxt-env module that stores variables in nuxt context this.$env. In most cases, you need your variables outside of nuxt context, for example baseURL for http-client, so it doesn't work well.
2. Use regex-powered script that replaces variables on every nuxt-server start. It works, but you'll have to store your variables keys both in script-file and docker-file to make it work. Not perfect.
3. Use window.__CONFIG__ = {} object hardcoded into page template. This only works for SPA-projects.

How does it work

Basically it is the second solution I mentioned above (marker-replacer-script), but this time you don't need to think about implementation, it just works*.

1. Before Nuxt started building its bundle, the module iterates every variable you mentioned in env option of nuxt.config.js and replaces it with a special marker: %%INJECTED_VARKEY%%
2. Nuxt builds a bundle that has markers instead of actual variables values, for example baseURL: '%%INJECTED_VARKEY%%'. At this point the bundle will be saved inside of Docker image.
3. You are trying to start the Docker image I mentioned above. Before Nuxt starts, the module iterates though every .js file inside of .nuxt dir and replaces markers with actual variables you passed to your Docker image.
4. Voilà. You have your Nuxt-app running only with variables that you used for docker run command (or in your CD config).

How to use

WIP. Check /example/README.md for now.

Caveats ⚠️ ⚠️ ⚠️

Don't use with NODE_ENV or flag-variables. Doesn't work with variables that are used in head section of nuxt.config. You need all your env vars to be passed to docker run, values assigned on build-time will be ereased. Module logic is not ideal, it is ⚠️ Work In Progress ⚠️.

Turns out there is a simillar project, you can try it instead.