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swiftvalue-typereference-type

Check for value or reference type in Swift

How can we check if a parameter passed in a function is a value or a reference type? For example

func isReferenceType(toTest: Any) {
    return true // or false
}

As we see here, we are not able to do this leveraging generics.

Solution

  • AnyObject is a protocol that any class type automatically conforms to, so you can write:

    func isReferenceType(toTest: Any) -> Bool {
    return toTest.dynamicType is AnyObject
}

class Foo { }
struct Bar { }

isReferenceType(Foo())    // true
isReferenceType(Bar())    // false
isReferenceType("foo")    // false
isReferenceType(123)      // false
isReferenceType([1,2,3])  // false