How to use custom js codes in ionic?

Hi, I want to use some modules like open mobile camera or select file from device and so on, but I’m making pwa and not mobile app using ionic, now if I use cordova or native library of ionic for those purpose, some mobile devices will have trouble.
With these conditions, I have already written pure js code for those purpose but I don’t know how to use them in ionic project. anyone can help me?