ng2-pdf-viewer VS angular-builders

The commit that adds the code denotes it as adding "analytics". So this app is probably intended to be the live demo on the author's website and not actually malicious.

You can check out his repo at: https://github.com/just-jeb/angular-builders

How does it work in Jest? The secret sauce is the jest-angular-preset project. It holds all the logic, and the Nx and just-jeb/angular-builders depend on it.

I already did it using Angular custom webpack and a custom build script I included in my angular.json file. You can just read the system env variables from the parameters provided by webpack and insert them using the webpack.DefinePlugin().

You would need a custom webpack config using asset modules to do this.

I think most people use this plugin if they want to customize the webpack config: https://github.com/just-jeb/angular-builders/tree/master/packages/custom-webpack

I use a custom webpack builder for this. There's a bit of pre-req setup to do in your angular.json, but after that you can run your own webpack script for any of your build configurations.