OB Copy

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4D v18

OB Copy


OB Copy ( object {; resolvePtrs} ) -> Function result

Parameter	Type	Description
object	Object, Object Field	Structured object
resolvePtrs	Boolean	True = resolve pointers, False or omitted = do not resolve pointers
Function result	Object	Deep copy of object

Description

The OB Copy command returns an object containing a complete (deep) copy of the properties, sub-objects and values for the object.

object must have been defined using the C_OBJECT command or designate a 4D object field.

If object contains pointer type values, by default the copy also contains the pointers. However, you can resolve pointers when copying by passing True in the resolvePtrs parameter. In this case, each pointer present as a value in object is evaluated when copying and its dereferenced value is used.

Notes:

If properties of object are shared objects or shared collections, they become standard (not shared) objects or collections in the returned copy.
Datastore, dataclass, entity, entity selection objects are not copiable. If OB Copy command is called with them, a Null value is returned.

Example 1

You want to duplicate an object containing simple values:

 C_OBJECT($Object)

 C_TEXT($JsonString)

 

 ARRAY OBJECT($arraySel;0)

 ALL RECORDS([Product])

 While(Not(End selection([Product])))

    OB SET($Object;"id";[Product]ID_Product)

    OB SET($Object;"Product Name";[Product]Product_Name)

    OB SET($Object;"Price";[Product]Price)

    OB SET($Object;"Tax rate";[Product]Tax_rate)

    $ref_value:=OB Copy($Object) //direct copy

    APPEND TO ARRAY($arraySel;$ref_value)

  //the contents of $ref_value are identical to those of $Object

    NEXT RECORD([Product])

 End while

  //the contents of $ref_value

 $JsonString:=JSON Stringify array($arraySel)

Example 2

You duplicate an object containing pointers:

 C_OBJECT($ref)

 

 OB SET($ref;"name";->[Company]name) //object with pointers

 OB SET($ref;"country";->[Company]country)

 ARRAY OBJECT($sel;0)

 ARRAY OBJECT($sel2;0)

 

 ALL RECORDS([Company])

 

 While(Not(End selection([Company])))

    $ref_comp:=OB Copy($ref) // copy without evaluating pointers

  // $ref_comp={"name":"->[Company]name","country":"->[Company]Country"}

    $ref_comp2:=OB Copy($ref;True) //copy with evaluation of pointers

  // $ref_comp={"name":"4D SAS","country":"France"}

    APPEND TO ARRAY($sel;$ref_comp)

    APPEND TO ARRAY($sel2;$ref_comp2)

    NEXT RECORD([Company])

 End while

 

 $Object:=JSON Stringify array($sel)

 $Object2:=JSON Stringify array($sel2)

 

  // $Object = [{"name":"","country":""},{"name":"","country":""},...]

  // $Object2 = [{"name":"4D SAS","country":"France"},{"name":"4D, Inc","country":"USA"},{"name":"Catalan","country":"France"}...]