- 2020-03-30 00:39:12
If the operator of typeof is a number, string, or Boolean, the result it returns is "number, ""string," or "Boolean." for objects, arrays, or null, it returns
"Object" returns "function" for a function operand, if the operand is undefined, it returns "undefined".
Typeof returns "object" when its operand is a wrapper object such as Number, String, or Boolean, and "object" for Date and RegExp objects.