Override property name to generate a JSON message

Here's a sample, using %ToDynamicObject (2016.2+):

Class DC.CustomJSONSample extends %RegisteredObject
{
Property myProperty As %String [ InitialExpression = "hello" ];

Property other As %String [ InitialExpression = "world" ];

/// Rename myProperty to custom_property_name
Method %ToDynamicObject(target As %Object = "", ignoreUnknown = 0) [ ServerOnly = 1 ]
{
	Do ##super(.target,.ignoreUnknown)
	Do target.$set("custom_property_name",target.myProperty,target.$getTypeOf("myProperty"))
	Do target.$remove("myProperty")
}

ClassMethod Run()
{
	Set tObj = ..%New()
	Write tObj.$toJSON()
}

}

Output:

SAMPLES>d ##class(DC.CustomJSONSample).Run()
{"other":"world","custom_property_name":"hello"}

For other discussions with solutions/examples involving %ToDynamicObject, see:
https://community.intersystems.com/post/json-cache-and-datetime
https://community.intersystems.com/post/create-dynamic-object-object-id