首先看浏览器调试Console中的答案:
[]+{} 结果是 "[object Object]"
{}+[] 结果是 0
({}+[]) 结果是 "[object Object]"
+[] 结果是 0 ,此处+为正号
+{} 结果是 NaN ,此处+为正号
[].toString() 结果是 ""
({}).toString() 结果是 "[object Object]"
{}.toString() 会出错,Uncaught SyntaxError: Unexpected token .
0+[] 结果是 "0"
0+{} 结果是 "0[object Object]"
https://blog.csdn.net/carcarrot/article/details/97786733