---
title: "isInstance(of:)"
framework: javascriptcore
role: symbol
role_heading: Instance Method
path: "javascriptcore/jsvalue/isinstance(of:)"
---

# isInstance(of:)

Returns a Boolean value indicating whether the value is an instance of another JavaScript object value.

## Declaration

```swift
func isInstance(of value: Any!) -> Bool
```

## Parameters

- `value`: The value to be compared against.

## Return Value

Return Value true if this value inherits from value; otherwise, false.

## Discussion

Discussion This method is analogous to the instanceof operator in JavaScript: it tests for the presence of the specified value’s constructor prototype in this value’s prototype chain.

## See Also

### Comparing JavaScript Values

- [isEqual(to:)](javascriptcore/jsvalue/isequal(to:).md)
- [isEqualWithTypeCoercion(to:)](javascriptcore/jsvalue/isequalwithtypecoercion(to:).md)