Singleton Pattern with {}?
I apologize to move it from here as there was some confusion and thanks to Grey for answer this to realized the mistake. The topic has been moved to Javascript: Behavior of {} to discuss further.
Singleton Pattern with '{}'. Here how it is:
var A = {
B : 0
};
// A is an object?
document.write("A is an " + typeof A);
Lets try to clone object A
var objectOfA = new Object(A);
objectOfA.B = 1;
//Such operation is not allowed!
//var objectOfA = new A();
var referenceOfA = A;
referenceOfA.B = -1;
document.write("A.B: " + A.B);
document.write("<br/>");
The above referenceOfA.B
holds a reference of object A
, so changing the value of referenceOfA.B
surely reflects in A.B
.
document.write("referenceOfA开发者_运维技巧.B: " + referenceOfA.B);
document.write("<br/>");
If successfully cloned then objectOfA
should hold value 1
document.write("objectOfA.B: " + objectOfA.B);
document.write("<br/>");
Here are the results:
A is an object
A.B: -1
referenceOfA.B: -1
objectOfA.B: -1
Upto here everything is clear but an object should take instanceof
on it. But here if you try to use instanceof
with A
you got an exception.
Why?
I don't get an exception:
alert(A instanceof Object); // true
Tested in Chrome, IE8 and Firefox.
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