###年后开启前端面试刷街模式，积累的一些js基础，欢迎添加更新，或是指正错误

1. 特殊字符比较

console.log(null==NaN)                          falseconsole.log(null==undefined)                    trueconsole.log(null==false)                        trueconsole.log(false=="")                          trueconsole.log(false==0)                           trueconsole.log(2+1+'3')                            '33'console.log('3'+2+1)                            '321'console.log(Number(undefined))                  NaNconsole.log(Number(''))                         0console.log(isNaN(23))                          trueconsole.log(typeof NaN)                         Numberconsole.log(isNaN(NaN))                         trueconsole.log(NaN==NaN)                           falseconsole.log(undefined===undefined)              true复制代码

2.变量提升

function t(a){    var a ='hello';    console.log(a);    function a(){        console.log(null);    }    console.log(a);}t(null);               ***************** hello   hellofunction a(b){    console.log(b);    b=function(){        alert(b);    }}a();                   ****************  undefinedfunction fn(b){    console.log(b);    function b(){        console.log(b);    }    b();                 }fn(1)                  *************** function b(){...}  function b(){...}复制代码

3.数组去重，取最大值

随机打印1-100 的10个数字，去重后取出数组中的最大值和最小值

function randomArray(){    var resul=[];    while(resul.length<10){        resul.push(Math.floor(Math.random()*100));        resul= [...new Set(resul)];    }    return resul;}var maxvalue =Math.max(...randomArray())var minvalue =Math.min(...randomArray())复制代码