is_defined

The following is a list of properties for the function is_defined:

Property	Value
`brief`	Is defined
`category`	miscellaneous
`description`	Test value returning boolean True if it is not undefined.
`functionId`	is_defined
`functionLabel`	is_defined
`parameters`	[ { "canBeUndefined": true, "description": "Value to check", "name": "value" } ]
`pure`	true
`returns`	{ "dataType": "boolean", "description": "True if value is not undefined." }