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Duplicate
Last update:
May 18, 2026
Note:
As of ColdFusion (2021 release), CORBA has been removed. You can no longer use CORBA-related features, functions, and tags.
Description
Returns a clone, also known as a deep copy, of a variable. There is no reference to the original variable.
Returns
A clone of a variable.
Category
Function syntax
Duplicate(object)See also
StructCopy, other Structure functions; Modifying a ColdFusion XML object in the Developing ColdFusion Applications
History
- ColdFusion (2025 release): Added an optional parameter, deepCopy.
- ColdFusion (2018 release): Introduced named parameters.
- ColdFusion 8: Changed behavior: this function can duplicate CFCs.
- ColdFusion MX: Changed behavior: this function can be used on XML objects.
Parameters
Parameter | Type | Description |
object | Name of a variable to duplicate | |
| deepCopy | Boolean | If deepCopy is TRUE, the child elements are cloned. If deepCopy is FALSE, child elements remain linked to their respective elements in the original object. |
Usage
Use this function to duplicate complex structures, such as nested structures and queries.When you duplicate a CFC instance, the entire CFC contents is copied, including the values of the variables in the this scope at the time you call the Duplicate function. Thereafter, the two CFC instances are independent, and changes to one copy, for example by calling one of its functions, have no effect on the other copy.
Note: With this function, you cannot duplicate a COM, CORBA, or JAVA object returned from the cfobject tag or the CreateObject function. If an array element or structure field is a COM, CORBA, or JAVA object, you cannot duplicate the array or structure.
Example
<cfscript>
s1 = StructNew()
s1.nested = StructNew()
s1.nested.item = "original"
copy = StructCopy(s1)
clone = Duplicate(s1)
// modify the original struct
s1.nested.item = "modified"
writeOutput("The copy contains the modified value: " & copy.nested.item & "<br/>")
writeOutput("The duplicate contains the original value: " & clone.nested.item)
</cfscript>Example- deepCopy is TRUE
<cfscript>
originalStruct = {
name = "Alice",
address = {
street = "123 Main St",
city = "Wonderland"
},
mobile = 7777777777
}
// Create a deep & a shallow copy
deepCopy = duplicate(originalStruct);
shallowCopy = duplicate(originalStruct, true);
// Modify a nested property in the original struct
originalStruct.address.street = "456 Oak St";
// Display results
writeOutput(#deepCopy.address.street#& "<br/>"); // deep copy
writeOutput(#shallowCopy.address.street#); // shallow copy
</cfscript>Output
123 Main St
123 Main St
123 Main St
Example- deepCopy is False
<cfscript>
originalStruct = {
name = "Alice",
address = {
street = "123 Main St",
city = "Wonderland"
},
mobile = 7777777777
}
// Create a deep & a shallow copy
deepCopy = duplicate(originalStruct);
shallowCopy = duplicate(originalStruct, false);
// Modify a nested property in the original struct
originalStruct.address.street = "456 Oak St";
// Display results
writeOutput(#deepCopy.address.street#& "<br/>"); // deep copy
writeOutput(#shallowCopy.address.street#); // shallow copy
</cfscript>Output
123 Main St
456 Oak St
456 Oak St
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