Question: In development, I use `http://localhost:565565/api/v2` in an angular service to retrieve data from local server.

Now in production, I want to change that url to `https://www.data.com/api/v2`.

How to change with angluar cli ? I don't want manually change the big `main.xxxxxxx.js` file.

Until now I use `ng build --prod` but it is not enough.

Answer: 
Use the environments provided in angular.cli:

On environment.ts for development use 

```
export const environment = {
    production: false,
    apiUrl: 'http://localhost:565565/api/v2'
};

```

On environment.prod.ts for production use:

```
export const environment = {
      production: true,
      apiUrl: 'https://www.data.com/api/v2'
};

```

Then depending on which environment you run your app the corresponding file will be used. If you run ng serve environment.ts will be used, if you run ng build --prod environment.prod.ts will be used.

Additionally you will need to import environment to your ts to use apiUrl

example in ts 

```
import { environment } from './../environments/environment';

```

and use it as `environment.apiUrl`
Use environment file:

```
ng build --environment=production

export const environment = {  
  production: true,
  apiUrl: "prod_Url"
};

export const environment = {  
      production: false,
      apiUrl: "dev_Url"
    };

```