Instance Property

isUndefined

A Boolean value that indicates whether the instance corresponds to the JavaScript undefined value.

Declaration

@property(readonly) BOOL isUndefined;

Discussion

The JavaScript undefined value is used for variables that have not yet been assigned a value, for formal parameters in functions for which no actual parameter has been passed, and as the result of expressions or function calls that do not explicitly return a value. Note that undefined is not the same as null.

See Also

Determining the Type of a JavaScript Value

isNull

A Boolean value that indicates whether the instance corresponds to the JavaScript null value.

isBoolean

A Boolean value that indicates whether the instance is a JavaScript Boolean value.

isNumber

A Boolean value that indicates whether the instance is a JavaScript numeric value.

isString

A Boolean value that indicates whether the instance is a JavaScript String object.

isObject

A Boolean value that indicates whether the instance is a JavaScript object.

isArray

A Boolean value that indicates whether the instance is a JavaScript array value.

isDate

A Boolean value that indicates whether the instance is a JavaScript Date object.