keys(callback){
		this.db.connect((db)=>{
			let req = db.transaction(this.name,'readonly').objectStore(this.name).getAllKeys();
			req.onsuccess = (event) => {
				let keys = req.result;
				if( callback ){ callback(keys); }
			};
		});
	}
/**
	 * Get all keys in this ObjectStore
	 *
	 * @param {Function} callback - callback
	 */
Get all keys in this ObjectStore
@param {Function} callback - callback
Get all keys in this ObjectStore @param { Function } callback - callback
keys(callback){
		this.db.connect((db)=>{
			let req = db.transaction(this.name,'readonly').objectStore(this.name).getAllKeys();
			req.onsuccess = (event) => {
				let keys = req.result;
				if( callback ){ callback(keys); }
			};
		});
	}
keys ( callback ) { this . db . connect ( ( db ) => { let req = db . transaction ( this . name , 'readonly' ) . objectStore ( this . name ) . getAllKeys ( ) ; req . onsuccess = ( event ) => { let keys = req . result ; if ( callback ) { callback ( keys ) ; } } ; } ) ; }
Get all keys in this ObjectStore
 @param {Function} callback - callback
Get all keys in this ObjectStore @param { Function } callback - callback