Have you override the sass.config.js script to copy the needed css?
In package.json add a config to your own local sass.config.js
"config": {
"ionic_sass": "./scripts/sass.config.js"
},
then create your own local script
module.exports = {
includePaths: [
'node_modules/ionic-angular/themes',
'node_modules/ionicons/dist/scss',
'node_modules/cropperjs/dist'
]
};
finally add your import
@import "cropper";
in one of your scss file. I added it personally in app.component.scss
Note: When you gonna run ionic serve, if you modify something to a scss, the live reload my produce an error that the reload weren’t able to find that included css file. There is an open issue about that in the @scripts project of Ionic