Why ionic 4 application size is increasing gradually when I'm trying to modify the code

#1

I have developed an app in ionic 3 which size is 6.4MB when build normally. When I build in production mode it is 3.05MB and with release and production mode it is 2.7MB. But the same featured app with less number of plugins in ionic 4 sized 13MB in normal build and production mode. With release mode it is 11MB. How can I decrease the app size. And it have only 3 images. I have removed the webview plugin also. Please help with this. Thank you In advance.