How to get environment from Angular Component as "Library"?

Question

I'm creating Angular Library but have some problem about environment. I generated a application(parent) and library(child). How to get environment (it defined under parent) from child component that defined in library.

I generated apps like this.

ng version
# Angular CLI: 8.0.1
# Node: 10.15.3
# OS: darwin x64
# Angular: 8.0.0
ng new app-parent
cd app-parent
ng generate library lib-child

project structure like this.

$ tree -L 2
.
├── README.md
├── angular.json
├── browserslist
├── e2e
│   ├── protractor.conf.js
│   ├── src
│   └── tsconfig.json
├── karma.conf.js
├── package.json
├── projects
│   └── lib-child # <- wanna get environment from here!!
├── src
│   ├── app
│   ├── assets
│   ├── environments
│   ├── favicon.ico
│   ├── index.html
│   ├── main.ts
│   ├── polyfills.ts
│   ├── styles.sass
│   └── test.ts
├── tsconfig.app.json
├── tsconfig.json
├── tsconfig.spec.json
├── tslint.json
└── yarn.lock

I tried import as relative path like... import { environment } from '../../../src/environment'; But this solution can NOT use another app. Library should use some environment&apps. I'm finding a way to like this.

import { environment } from '@angular/core';

environment.production #=> true/false

Answer 1

I don't think passing the environment to a side project is a good practice,

Instead try passing it through the main app by creating a static method on the project's module:

import { environment } from '../../../src/environment';    
...

@NgModule({
  imports: [
    BrowserModule,
    MyProjectModule.forRoot({
      environment: environment
    }),
    ...
 ]})

and in the project module:

export class MyProjectModule {
  static forRoot(environment): ModuleWithProviders {
    // User envirnment here or decalare an injection token for the environment
    console.log(environment);
    return {
      ngModule: SampleModule,
      providers: [{provide: 'environment', useValue: environment}]
    };
  }
}