Managing large amounts of environment variables

从之前的 issue #4318 以及 build、serve、test 和 e2e 命令的入口点开始。检查现有的 environments.ts 方案和 webpack.config.js 中的 DefinePlugin 示例，然后确定应如何将导出的变量或 .env 文件作为 process.env.VARIABLE 暴露出来。当这些命令支持的行为和范围都已定义时，即视为完成。

Command

build, serve, test, e2e

Description

I am reopening https://github.com/angular/angular-cli/issues/4318.

Essentially we need a way to pass environment variables to the build/serve commands. environments.ts file is not a viable solution as you would need to end up with hundreds of environment.ts files depending on all the permutations per environment.

The solution to https://github.com/angular/angular-cli/issues/4318 also does not address this since you need to know the define values when running the command ng build <define> <define> <define>....
Which means you would have to generate the build command same way as generating the environment.ts file.

Most enterprise angular applications I have worked on ends up extending the webpack.config.js file adding:

DefinePlugin({
  process: {
    env: {
      VAR_1: JSON.stringify(process.env.VAR_1),
      ...
    }
  }
})

This issue has been brought up for years with the Angular repo but i've never seen a resolution so I want to try to make it as clear as possible.
We should support a dotenv() style solution where in the code we can use process.env.VARIABLE.
In the build machine we can either:
export VARIABLE=test
or have a .env file to pick it up.

This is supported by pretty much every other framework out there so I'm not sure why it wouldn't be possible or hasn't already been implemented.

If the issue is the angular team doesn't want this behaviour then that is fine but I am looking for a yes/no type answer. If the answer is no the angular team would be able to point to this issue for all future feature requests of this nature.

Describe the solution you'd like

No response

Describe alternatives you've considered

No response