/Ionic

Using environment config in Ionic2

After you finish building your app and you are ready to deploy to the App Stores you will realize that you need to use specific variables for the production environment that are different than your development environment. After a lot of reading and some experimentation I came upon what I consider the best and most versatile way to build apks and ipas that have different “settings” for development and production.

So say you have some specific values for each environment that you want to use throughout your app, lets first declare an interface for these values, so that typescript can help us not forget declaring any and we have an easier time using them in our code.

env.variables.ts

export interface IEnvironmentalVariables {
  apiUrl: string;
  googleOAuth: string;
  kmsApiKey: string;
  logToConsole: boolean;
}

then let’s declare some values for the development and production environments respectively:

env.develop.ts:

import { IEnvironmentalVariables } from './env.variables';

export const devConfig: IEnvironmentalVariables = {
  apiUrl: 'https://...',
  googleOAuth: '6047....apps.googleusercontent.com',
  kmsApiKey: '7a...1e',
  logToConsole: true
};

env.production.ts:

import { IEnvironmentalVariables } from './env.variables';

export const productionConfig: IEnvironmentalVariables = {
  apiUrl: 'https://...',
  googleOAuth: '6047....apps.googleusercontent.com',
  kmsApiKey: '7a...1e',
  logToConsole: false
};

We then need to declare an OpaqueToken so that we can use a simple string in Angular’s DI:

environment.token.ts:

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

// tslint:disable-next-line:variable-name
export const Environment = new OpaqueToken('environment');

and then lets declare out environment module:

environment.module.ts

import { NgModule } from '@angular/core';
import { Environment } from './environment.token';
import { productionConfig } from './env.production';
import { developConfig } from './env.develop';

export function environmentFactory() {
  switch (process.env.NODE_ENV) {
    case 'dev':
      return developConfig;
    case 'prod':
      return productionConfig;
    default:
      throw new Error('Enviroment not set');
  }
}

@NgModule({
  providers: [
    {
      provide: Environment,
      useFactory: environmentFactory
    }
  ]
})
export class EnvironmentsModule { }

This completes our module definition. We can now go ahead and use this module in any of our apps like following. We first import the module as usual in our main app module.

app.module.ts

import { EnvironmentsModule } from '../environment/environment.module';

@NgModule({
  ...
  imports: [
  ...
  EnvironmentsModule,
  ...
  ]
  ...
}

and whenever we need to use a config value we can inject our environment like:

my-class.ts:

class MyClass {
  constructor(@Inject(Environment) private _env: IEnvironmentalVariables){
      console.log(this._env.apiUrl); // different value depending on the environment
  }
}

The final steps that makes all the above take effect in the final built application is setting the NODE_ENV variable to the appropriate value. For instance to build an APK using the production config values we would run:

NODE_ENV=prod bash -c 'ionic cordova build android --prod --release'

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masimplo

Software engineer,father,cook,motorhead,carpenter

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