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Documentation below is for CLI version 6. For version 7 see here.

Application Environments

In Angular CLI you can configure the build system to replace existing files for your intended environment.

Configuring available file replacements

angular.json contains an fileReplacements section within the production configuration of the build target. By default, this looks like:

"configurations": {
  "production": {
    "fileReplacements": [
      {
        "replace": "src/environments/environment.ts",
        "with": "src/environments/environment.prod.ts"
      }
    ],
    ...

This means that when you use your production configuration (via ng build --prod or ng build --configuration=production), the src/environments/environment.ts file will be replaced with src/environments/environment.prod.ts.

This is useful for using different code or variables when creating a new build. By default no file is replaced in the build.

You can add additional configurations as required. To add a staging environment, create a copy of src/environments/environment.ts called src/environments/environment.staging.ts, then add a staging configuration to angular.json:

"configurations": {
  "production": { ... },
  "staging": {
    "fileReplacements": [
      {
        "replace": "src/environments/environment.ts",
        "with": "src/environments/environment.staging.ts"
      }
    ]
  }
}

You can add more configuration options to this environment as well. Any option that your build supports can be overriden in a configuration.

To build using the staging configuration, run ng build --configuration=staging.

To serve using the staging configuration, you must edit the serve target to use the staging build configuration:

"serve": {
  "builder": "@angular-devkit/build-angular:dev-server",
  "options": {
    "browserTarget": "your-project-name:build"
  },
  "configurations": {
    "production": {
      "browserTarget": "your-project-name:build:production"
    },
    "staging": {
      "browserTarget": "your-project-name:build:staging"
    }
  }
},

Changing environment-specific files

environment.ts contains the default settings. If you take a look at this file, it should look like:

export const environment = {
  production: false
};

If you compare this to environment.prod.ts, which looks like:

export const environment = {
  production: true
};

You can add further variables, either as additional properties on the environment object, or as separate objects, for example:

export const environment = {
  production: false,
  apiUrl: 'http://my-api-url'
};

Using environment-specific variables in your application

Given the following application structure:

└── src
    └── app
        ├── app.component.html
        └── app.component.ts
    └── environments
        ├── environment.prod.ts
        ├── environment.staging.ts
        └── environment.ts

Using environment variables inside of app.component.ts might look something like this:

import { Component } from '@angular/core';
import { environment } from './../environments/environment';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  constructor() {
    console.log(environment.production); // Logs false for default environment
  }
  title = 'app works!';
}

You will always import the original environments file. This way the build system can replace the original in each configuration.