Why can't read google map api ionic v4

Ionic Framework ionic-v3
1

Environment.setEnv({
// api key for server
‘API_KEY_FOR_BROWSER_RELEASE’: ‘(*******************************)’,

    // api key for local development
    'API_KEY_FOR_BROWSER_DEBUG': 'http://localhost/'
  });

response error page:

ERROR Error: Uncaught (in promise): TypeError: Cannot read property 'environment' of null
TypeError: Cannot read property 'environment' of null
2

why please help me ?

3

Check this https://stackoverflow.com/questions/52657414/runtime-error-cannot-read-property-environment-of-null-ionic-google-maps/52681481#52681481