---
title: "reverseTransformedValue(_:)"
framework: foundation
role: symbol
role_heading: Instance Method
path: "foundation/valuetransformer/reversetransformedvalue(_:)"
---

# reverseTransformedValue(_:)

Returns the result of the reverse transformation of a given value.

## Declaration

```swift
func reverseTransformedValue(_ value: Any?) -> Any?
```

## Parameters

- `value`: The value to reverse transform.

## Return Value

Return Value The reverse transformation of value.

## Discussion

Discussion The default implementation raises an exception if allowsReverseTransformation() returns false; otherwise it will invoke transformedValue(_:) with value. A subclass should override this method if they require a reverse transformation that is not the same as simply reapplying the original transform (as would be the case with negation, for example). For example, if a value transformer converts a value in Fahrenheit to Celsius, this method would converts a value from Celsius to Fahrenheit.

## See Also

### Transforming Values

- [transformedValue(_:)](foundation/valuetransformer/transformedvalue(_:).md)