常用函数

去重：

1. （两个es6知识点set/...)

let arr = [1,2,3,4,1];
let set = new Set(arr)
// set 转 arr
let arr2 = [...set];

let arr3 = Array.from(set)

copyToClipboard - 复制到剪贴板

const copyToClipboard = str => {
  const el = document.createElement('textarea');
  el.value = str;
  el.setAttribute('readonly', '');
  el.style.position = 'absolute';
  el.style.left = '-9999px';
  document.body.appendChild(el);
  const selected =
    document.getSelection().rangeCount > 0 ? document.getSelection().getRangeAt(0) : false;
  el.select();
  document.execCommand('copy');
  document.body.removeChild(el);
  if (selected) {
    document.getSelection().removeAllRanges();
    document.getSelection().addRange(selected);
  }
};

回到顶部：

const scrollToTop = () => {
  const c = document.documentElement.scrollTop || document.body.scrollTop;
  if (c > 0) {
    window.requestAnimationFrame(scrollToTop);
    window.scrollTo(0, c - c / 8);
  }
};

ps:

scrollTo=scroll(但是官网建议频次高的话用scrollTop，scrollBy是相对定位）

 function param2Obj(url) {
        const search = url.split('?')[1]
        if (!search) {
            return {}
        }
        return JSON.parse(
            '{"' +
            decodeURIComponent(search)
                .replace(/"/g, '\"')
                .replace(/&/g, '","')
                .replace(/=/g, '":"') +
            '"}'
        )
    }
    function setCookie(cname, cvalue, exdays) {
      var d = new Date();
      d.setTime(d.getTime() + exdays * 24 * 60 * 60 * 1000);
      document.cookie = `${cname}=${cvalue};expires=${d}}`;
    }
    function getCookie(cname){
        var ca = document.cookie.split(';');
        var name = cname +'=';
        for(var i=0;i<ca.length;i++){
            var c = ca[i];
            if(c.indexOf(name)==0){
                return c.substring(name.length,c.length)
            }
        }
    }