//Basically what we are doing is hooking into ckeditor upload adapter plugin scheme and replace XHR request to server with a simple base64 encoding function
class Base64Adapter {
    constructor( loader ) {
        this.loader = loader;
    }
    upload() {
        return this.loader.file
            .then( file => new Promise( ( resolve, reject ) => {
                const reader = new FileReader();
                reader.readAsDataURL(file);
                reader.onload = () => resolve({default:reader.result});
                reader.onerror = error => reject(error);
            } ) );
    }
    abort() {
      console.log('Fake Abort');
    }
}

function Base64AdapterPlugin( editor ) {
    editor.plugins.get( 'FileRepository' ).createUploadAdapter = ( loader ) => {
        return new Base64Adapter( loader );
    };
}