javascript -typeof

https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Operators/typeof

Undefined	未定义	Boolean	Null	Number	Function	Array
'undifined'	'undifined'	"boolean"	"object"	'number'	'function'	'object'

Infinity	NaN
'number'	'number'

new Function()	new String('String')	new Number(100)	new Boolean(true)	class C{}
'function'	"object"	'object'	'object'	'function'

typeof /s/
不同浏览器不一样，"object" 或者 'function'