Importance of environment setting in Codeigniter

Codeigniter contains an environment setting in index.php. which is used to disable the error showing in the frontend of the website or UI. By default the environment comes with development here, we can see the errors that occur during the development of our website. After successful completion of the website, we have to change the environment as production by enabling this it hides the error showing in the frontend. there is another type of environment called testing which is used the testing time of our website.