Properties
				
				
					
					Optional onComplete
					onComplete: undefined | ((target?: undefined | object) => void)
					
					
				
				
					
					Optional onStart
					onStart: undefined | ((target?: undefined | object) => void)
					
					
				
				
					
					Optional onUpdate
					onUpdate: undefined | ((target?: undefined | object, ratio?: undefined | number) => void)
					
					
				
				
					
					Optional progress
					progress: undefined | ((start: number, end: number, current: number, ratio: number) => number)
					
					
				
			
		 
缓动的可选属性的接口定义。