//?this.x,?this.startX,?duration,?this.maxScrollX|Y,?this.options.bounce???this.wrapperWidth|Height?:?0,?this.options???? export?function?momentum(current,?start,?time,?lowerMargin,?wrapperSize,?options)?{???? let?distance?=?current?-?start;???? let?speed?=?Math.abs(distance)?/?time;???? //??deceleration?=?0.001,?itemHeight,?swipeBounceTime?=?1200,?bounceTime?=?700???? let?{deceleration,?itemHeight,?swipeBounceTime,?bounceTime}?=?options;???? //?swipeTime?=?2500???? let?duration?=?options.swipeTime;???? let?rate?=?options.wheel???4?:?15;???? //????? //?(distance?<?0???-1?:?1)?判斷往上滾動，還是往下滾動???? let?destination?=?current?+?speed?/?deceleration?*?(distance?<?0???-1?:?1);???? if?(options.wheel?&&?itemHeight)?{???? destination?=?Math.round(destination?/?itemHeight)?*?itemHeight;???? }???? //?destination?<?lowerMargin判斷往(下|右)方向,?destination?>?0?相反???? if?(destination?<?lowerMargin)?{???? //????? destination?=?wrapperSize???lowerMargin?-?(wrapperSize?/?rate?*?speed)?:?lowerMargin;???? duration?=?swipeBounceTime?-?bounceTime;???? }?else?if?(destination?>?0)?{???? //???? destination?=?wrapperSize???wrapperSize?/?rate?*?speed?:?0;???? duration?=?swipeBounceTime?-?bounceTime;???? }???? return?{???? destination:?Math.round(destination),???? duration???? };???? };