Close ionic 4 app on button click

Question

Hi,

I am developing an ioinc 4 app. Now i am trying to exit the app when user click the button.

I am trying to write the logic 

" this.plateform.exitApp() "

the error is 

" Property 'exitApp' does not  exist on type 'plateform'  " .

any one who have idea about ionic 4?

 

help will be appreciated

Thank you