instanceof to detect whether an object An is an instance of another object B is to see if the object pointed to by the prototype of object B is on the [[prototype]] chain of object A. That
"".__proto__===String.prototype
true
"" instanceof String
false
String.prototype"" falseconvert it to a string instance when performing a point operation on the literal amount of a string
because " is not an object, but the original data type.
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