text: const ACTIVE = 'lh_active';
  const onLazyHide = function (opts) {
  	const RETAIN_TOP = opts.top;
  	const el_wrapper = opts.el;
  
  	let _isHide = false;
  
  	const negative = () => {
  		_isHide = true;
  		el_wrapper.classList.remove(ACTIVE);
  	}
  
  	const active = () => {
  		_isHide = false;
  		el_wrapper.classList.add(ACTIVE);
  	}
  
  	let timer = false, topArr = [];
  	const direction = (top) => {
  		if (Math.abs(topArr[0] - topArr[2]) < 100) {
  			return;
  		}
  
  		let ret = 0;
  		if (topArr[0] < topArr[1] && topArr[1] < topArr[2]) {
  			ret = 1;
  		} else if (topArr[0] > topArr[1] && topArr[1] > topArr[2]) {
  			ret = -1;
  		}
  
  		if (ret == 1) {
  			negative();
  		} else if (ret == -1) {
  			active();
  		}
  	}
  
  	const scrollJudge = (top) => {
  		if (!timer) {
  			timer = true;
  
  			if (topArr.length < 3) {
  				topArr.push(top);
  			} else {
  				direction();
  				topArr = [];
  			}
  
  			setTimeout( function () {
  				timer = false;
  			}, 50);
  		}
  	}
  
  	window.addEventListener('scroll', (e) => {
  		const top = document.body.scrollTop;
  
  		if (top > RETAIN_TOP) {
  			scrollJudge(top);
  		} else {
  			if (_isHide) {
  				active();
  			}
  		}
  	});
  
  	el_wrapper.classList.add(ACTIVE);
  }
  
  module.exports = onLazyHide;
  