IONIC_ENVIRONMENT TypeScript

Ionic Framework ionic-v3
1

Ionic Environment Variable says to use:

if (process.env.IONIC_ENV === 'prod') {
  console.log('we got a production buildp');
} else {
  console.log('we got a development build');
}

But on TypeScript I have to import that process variable, right?

How? Could we specify that on documentation?