mUtils.js

/**
 * 存储localStorage
 */
const setStore = (name, content) => {
	if (!name) return;
	if (typeof content !== 'string') {
		content = JSON.stringify(content);
	}
	window.localStorage.setItem(name, content);
}

/**
 * 获取localStorage
 */
const getStore = name => {
	if (!name) return;
	return window.localStorage.getItem(name);
}

/**
 * 删除localStorage
 */
const removeStore = name => {
	if (!name) return;
	window.localStorage.removeItem(name);
}

/**
 * 获取style样式
 */
const getStyle =  (obj,attr) => { 
    if(obj.currentStyle){ 
        return obj.currentStyle[attr]; 
    } 
    else{ 
        return document.defaultView.getComputedStyle(obj,null)[attr]; 
    } 
} 

/**
 * 页面到达底部，加载更多
 */
const loadMore =  (el, callback) => {
	let windowHeight = window.screen.height;
	let height;
	let setTop;
	let paddingBottom;
	let marginBottom;
    let requestFram;
    let oldScrollTop;

	el.addEventListener('touchstart',() => {
        height = el.offsetHeight;
        setTop = el.offsetTop;
        paddingBottom = parseInt(getStyle(el,'paddingBottom'));
        marginBottom = parseInt(getStyle(el,'marginBottom'));
    },false)

    el.addEventListener('touchmove',() => {
       loadMore();
    },false)

    el.addEventListener('touchend',() => {
       	oldScrollTop = document.body.scrollTop;
       	moveEnd();
    },false)
    
    const moveEnd = () => {
        requestFram = requestAnimationFrame(() => {
            if (document.body.scrollTop != oldScrollTop) {
                oldScrollTop = document.body.scrollTop;
                moveEnd();
            }else{
            	cancelAnimationFrame(requestFram);
            	//为了防止鼠标抬起时已经渲染好数据从而导致重获取数据，应该重新获取dom高度
            	height = el.offsetHeight;
                loadMore();
            }
        })
    }

    const loadMore = () => {
        if (document.body.scrollTop + windowHeight >= height + setTop + paddingBottom + marginBottom) {
            callback();
        }
    }
}

/**
 * 显示返回顶部按钮
 */
const showBack =  callback => {
    let requestFram;
    let oldScrollTop;

    document.addEventListener('touchstart',() => {
       showBackFun();
    },false)

    document.addEventListener('touchmove',() => {
       showBackFun();
    },false)

    document.addEventListener('touchend',() => {
        oldScrollTop = document.body.scrollTop;
        moveEnd();
    },false)
    
    const moveEnd = () => {
        requestFram = requestAnimationFrame(() => {
            if (document.body.scrollTop != oldScrollTop) {
                oldScrollTop = document.body.scrollTop;
                showBackFun();
                moveEnd();
            }else{
                cancelAnimationFrame(requestFram);
            }
        })
    }

    const showBackFun = () => {
        if (document.body.scrollTop > 500) {
            callback(true);
        }else{
            callback(false);
        }
    }
}


export {setStore, getStore, removeStore, getStyle, loadMore, showBack}