What problem does this library solve?

Many Angular applications depend on configuration to modify application behaviour. You may want multiple instances of the same Angular app to behave differently based on some configuration. Angular provides a way to do this at build time but often this solution is not flexible enough if engineers want to configure their app after it's been built/deployed.

ngx-runtime-env solves this. It fetches an application environment at runtime, and then mutates the existing Angular environment accordingly. See Usage for an example.

Install

npm i ngx-runtime-env

or

yarn add ngx-runtime-env

Usage

In: src/environments/environment.ts (static)

export const environment = {
  production: false,
  foo: 'bar',
};

In: assets/environment.json (dynamic, picked up at runtime, will mutate static environment)

{
    "production": true,
    "foo": "baz",
}

In: app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppComponent } from './app.component';
import { HttpClientModule } from '@angular/common/http';
import { RuntimeEnvModule } from 'ngx-runtime-env';
import { environment } from '../environments/environment';

@NgModule({
  declarations: [ AppComponent ],
  imports: [ 
    BrowserModule,
    // import HttpClientModule
    HttpClientModule,
    // import RuntimeEnvModule module and pass in static environment
    RuntimeEnvModule.forRoot(environment)
  ],
  providers: [],
  bootstrap: [ AppComponent ]
})
export class AppModule {}

In a component (app.component.ts for example)

import { Component, OnInit } from '@angular/core';
import { environment } from 'src/environments/environment';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent implements OnInit {

  ngOnInit(): void {
    console.log(environment.production); // true
    console.log(environment.foo); // baz
  }
}

Configuration

Name	Type	Default	Description
envUrl	string	assets/environment.json	Specify where the runtime environment can be found.
bootstrapAppModule	'before' | 'after'	'after'	Whether to bootstrap the application module before or after the runtime environment is loaded.
optional	boolean	false	If true, application will bootstrap normally even if runtime environment fails to be found

Example

In: app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppComponent } from './app.component';
import { HttpClientModule } from '@angular/common/http';
import { RuntimeEnvModule } from 'ngx-runtime-env';
import { environment } from '../environments/environment';

@NgModule({
  declarations: [ AppComponent ],
  imports: [ 
    BrowserModule,
    HttpClientModule,
    RuntimeEnvModule.forRoot(environment, {
      envUrl: '/path/to/my/config', // looks for runtime environment in envUrl
      bootstrapAppModule: 'before' // does not wait for runtime environment to bootstrap App Module
    })
  ],
  providers: [],
  bootstrap: [ AppComponent ]
})
export class AppModule {}