Is there a JavaScript Object that is not a function?
javascript: x=y=z=Object; alert([window.navigator.userAgent,x,y,z].join("\n\n"))
(There was a comment that x
,y
,z
are merely references in which case Object
is also merely a reference to function Object(){ ... }
because Object
's value is assigned to x
and they are the "same". As "proof"
javascript:x=Object;x.p=43;alert([x==Object,x===Object,x.p,Object.p])
displays
true,true,43,43
Given function Thing(){}
does x=new Thing()
make x
an object or a reference to one? What about new Thing()
and Thing
? Or y
in y=x=new Thing()
or y=x=Thing
? What if Thing=function(){}
? The distinction is moot. "Everything" (or is it?) is called-by-reference but call-by-name can be coerced by evaluating strings. So ...)
javascript:
void function(x,y,z){
alert( [window.navigator.userAgent,x,y,z].join("\n\n") )
}(Object,Object,Object)
or
javascript:
void function(x){ (function (y){ (function (z){
alert( [window.navigator.userAgent,x,y,z].join("\n\n") )
})(y) })(x) }(Object)
(well not quite moot - the function
's values must be coerced using (...)
or void
. The nuances of (...)
are subtle:
javascript: /* 43.p gives a runtime error but not ... */
alert([ (43).p=34, 43["q"]=17, (x=43).z="hmmm" ]);
alert([ 43["p"], (43).z, x.p, x["z"], x]);
displays 34,17,hmmm
and ,,,,43
)
or even an array of Objects
javascript:alert([window.navigator.userAgent,Object,Object,Object].join("\n\n"))
gives:
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.3) Gecko/20100423 Ubuntu/10.04 (lucid) Firefox/3.6.3
function Object() { [native code] }
function Object() { [native code] }
function Object() { [native code] }
There are many objects that are not Object.
As pointed out in one of the answers, Object may not be itself IF it is modified.
Danger! Danger! Will Robinson!
x=y=z=Object=null; alert([window.navigator.userAgent,Object,x,y,z].join("\n\n"));
references
You didn't create objects, you created references to the Object function. If you wanted those to be objects you could do this:
x = y = z = {}
Then alert(x)
will return object [Object]
.
To (hopefully) encompass the comments - by default Object
is a Function which constructs Objects. If you reassign the name Object (Firefox at least seems to allow me to, haven't tested all browsers) then Object
will no longer be a Function, it will be whatever you assigned to it. So then, the answer is "no", Object is not always a Function, but should be unless it has been explicitly re-declared. According to Firebug:
>>> Object
Object()
>>> Object = {}
Object {}
>>> Object
Object {}
Seemingly it can be reassigned. I cannot vouch for what kind of impacts that would have, if any.
You are assigning the Object constructor to the vars x, y and z.
If you instead say x=new Object()
, you will no longer see them referred to as functions.
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