allow PORT configuration at app startup

I’m submitting a … (check one with “x”)

[ ] Regression (a behavior that used to work and stopped working in a new release)
[ ] Bug report  <!-- Please check the repository for a similar issue or PR before submitting -->
[ ] Support request => <!-- Please check the repository for a similar issue or PR before submitting -->
[ ] Feature request
[x ] Documentation issue or request

Current behavior

Setting env variable PORT to a desired value prior to running npm run serve has no impact on the app.

Expected/desired behavior

Setting PORT env variable before running npm run serve configures the express server to listen on the specified port.

What is the motivation / use case for changing the behavior?

I am still a noob to webpack and angular 2 so I apologise if this is a dumb question. I am aware that setting the environment variable PORT at build time will bake the PORT into the app. Unfortunately, I only know which PORT to expose at app startup. This is a restriction imposed on me by my hosting platform, and I feel not an unreasonable one. I am pretty sure this is very possible, and probably quite a common use case, I just can’t find the appropriate docs and my experiments have yielded no fruit!

Environment

• Angular version: 4.4.1

[rallu]

Having DefinePlugin in the project that has NodeJS server is a bad idea in my opinion. It prevents use cases like this (I had the same problem) and other cases where you need really to have system ENV variables for you.

I would suggest that ng-seed/universal would build their own env system totally separate from system ENV.

[fulls1z3]

@Angry-Potato @rallu if you feel that an own env system totally separate from system ENV, you can always contribute with your use cases/ideas as well as PRs to this repo and angular-webpack-config.