Followed this DJAM URL
$ ionic cordova plugin add cordova-plugin-crop
$ npm install @ionic-native/crop
$ ionic cordova plugin add cordova-plugin-camera
$ npm install @ionic-native/camera
$ ionic cordova plugin add cordova-plugin-file-transfer
$ npm install @ionic-native/file-transfer
$ ionic cordova plugin add cordova-plugin-file
$ npm install @ionic-native/file
$ ionic cordova plugin add cordova-plugin-ionic-webview
$ npm install @ionic-native/ionic-webview