---
title: "defaultValue(forKey:)"
framework: quartzcore
role: symbol
role_heading: Type Method
path: "quartzcore/caanimation/defaultvalue(forkey:)"
---

# defaultValue(forKey:)

Specifies the default value of the property with the specified key.

## Declaration

```swift
class func defaultValue(forKey key: String) -> Any?
```

## Parameters

- `key`: The name of one of the receiver’s properties.

## Return Value

Return Value The default value for the named property. Returns nil if no default value has been set.

## Discussion

Discussion If this method returns nil a suitable “zero” default value for the property is provided, based on the declared type of the key. For example, if key is a CGSize object, a size of (0.0,0.0) is returned. For a CGRect an empty rectangle is returned. For CGAffineTransform and CATransform3D, the appropriate identity matrix is returned. Special Considerations If key is not a known for property of the class, the result of the method is undefined.