---
title: isNumber
framework: javascriptcore
role: symbol
role_heading: Instance Property
path: javascriptcore/jsvalue/isnumber
---

# isNumber

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

## Declaration

```swift
var isNumber: Bool { get }
```

## Discussion

Discussion In JavaScript, there is no differentiation between types of numbers. Semantically, all numbers behave as double-precision floating-point types, except in special cases like bit operations.

## See Also

### Determining the Type of a JavaScript Value

- [isUndefined](javascriptcore/jsvalue/isundefined.md)
- [isNull](javascriptcore/jsvalue/isnull.md)
- [isBoolean](javascriptcore/jsvalue/isboolean.md)
- [isString](javascriptcore/jsvalue/isstring.md)
- [isObject](javascriptcore/jsvalue/isobject.md)
- [isArray](javascriptcore/jsvalue/isarray.md)
- [isDate](javascriptcore/jsvalue/isdate.md)
- [isSymbol](javascriptcore/jsvalue/issymbol.md)