今天神經(jīng)病又犯了，突發(fā)奇想的試試看對(duì)一些基本數(shù)值類(lèi)型應(yīng)用運(yùn)算，會(huì)出現(xiàn)啥現(xiàn)象。
先列出來(lái)一些類(lèi)型的數(shù)值
let obj = {a:1,b:2};??
obj+null;? //[object Object]null? ? ? ?
obj+undefined;? ?//[object Object]undefined
let num = 123;?
num+null;? ? //123
num+undefined;? ?//NaN
let str = 'aaa';
str+null;? ?//'aaanull'
str+undefined;? ? //"aaaundefined"
let str2 = '123';
function fn(){}
let arr = [1,2,3];
let n = null;
let u = undefined;
let t = true;
let f = false;
