Function instanceof Object and vice-versa ?

[System Administrator]

Hi:

Can someone explain why BOTH of the following are true ?

Function instanceof Object //true
Object instanceof Function //true


(Either one or the other should be true, not both, right ?)

Best regards,
--j

 

[VK]

Hi:

Can someone explain why BOTH of the following are true ?

Function instanceof Object //true
Object instanceof Function //true

(Either one or the other should be true, not both, right ?)

Wrong. This is prototype based language here, not a class based.
a instanceof b
check is a "syntax beautifying" for
b.prototype.isPrototypeOf(a)
While "making JavaScript out of LiveScript" one of requests to Brendan
Eich was to make the syntax closer to Java - because Java was cool
everything else lame at that time.

Now analyze the result with the actual meaning of instanceof in
javascript in mind. Overall until
http://blogs.msdn.com/ericlippert/archive/2003/11/06/53352.aspx
is fully read and understood you will keep getting a lot "puzzles"
like that one.

 

[RobG]

Hi:

Can someone explain why BOTH of the following are true ?

Function instanceof Object //true
Object instanceof Function //true

Function and Object are both constructors, and therefore functions.
And all functions are also objects.


So:

function x(){};
x instance of Object // true
x instance of Function // true

y = {};
y instanceof Object // true
y instanceof Function // false