Log NEXT_PUBLIC_* env vars in console build output

[malimccalla]

I have an app that runs in three different environments: test, development and production. At build time, in my Docker image, I dynamically set some variables using inlined environment variables dependant on the environment.

I would love to be able to see these values printed to the console with my build output. This would give me peace of mind that the correct values have been set. (I accidentally deployed my app to staging using http://localhost:4000 as my api endpoint 😅).

I imagine it would look something like this

Compiled successfully.

Automatically optimizing pages...

Page                                                           Size     First Load JS
┌ λ /                                                          4.89 kB         312 kB
├   /_app                                                      10.3 kB         307 kB
├ λ /404                                                       1.66 kB         309 kB
├ λ /change_password                                           2 kB            309 kB
├ λ /checkout                                                  5.09 kB         312 kB
├ λ /dashboard                                                 4.62 kB         312 kB
├ λ /forgot_password                                           1.66 kB         309 kB
├ λ /login                                                     1.72 kB         309 kB
├ λ /logout                                                    593 B           308 kB
├ λ /profile                                                   5.75 kB         313 kB
├ λ /register                                                  592 B           308 kB
├ λ /release                                                   7.35 kB         314 kB
├ λ /rewards                                                   1.74 kB         309 kB
├ λ /search                                                    2.58 kB         310 kB
├ λ /settings                                                  4.95 kB         312 kB
├ λ /subscribe                                                 5.56 kB         313 kB
└ λ /upgrade                                                   2.48 kB         310 kB
+ First Load JS shared by all                                  307 kB
  ├ static/pages/_app.js                                       10.3 kB
  ├ chunks/50467efda490a464ef2ab03cfb93643853659b93.4da9be.js  5.02 kB
  ├ chunks/8fcc81788b9314fe70ae1fa7873f5898a0588e83.5bbbdf.js  218 kB
  ├ chunks/commons.19bfab.js                                   20.5 kB
  ├ chunks/framework.66a1b4.js                                 45.5 kB
  ├ runtime/main.3b9212.js                                     6.11 kB
  └ runtime/webpack.f33d3f.js                                  1.47 kB

λ  (Server)  server-side renders at runtime (uses getInitialProps or getServerSideProps)
○  (Static)  automatically rendered as static HTML (uses no initial props)
●  (SSG)     automatically generated as static HTML + JSON (uses getStaticProps)

---------------------------------------------------------
       Environment variables inlined at build time
---------------------------------------------------------
NEXT_PUBLIC_API_ENDPOINT         https://api.example.com
NEXT_PUBLIC_APP_LOCALE           en-us
SOME_SECRET_KEY                  **********