react.md

####react笔记

#####react-lazy-load

要点:

######父级容器计算规则

overfolow=scroll || auto

######判断元素是否在父级容器

#1 父级容器区域:

top,left,offsetWidth,offsetHeight

#2 判断:

if (typeof container === 'undefined' || container === window) {
    top = window.pageYOffset;
    left = window.pageXOffset;
    bottom = top + window.innerHeight;
    right = left + window.innerWidth;
  } else {
    const containerOffset = offset(container);

    top = containerOffset.top;
    left = containerOffset.left;
    bottom = top + container.offsetHeight;
    right = left + container.offsetWidth;
  }

######兼容background-image

######需要配置offset及height

我一般设置offsetVertical

#####onlyActiveOnIndex

<Link onlyActiveOnIndex activeStyle={{color:'#53acff'}} to='/'>Home</Link>