Use this extension to check if a string represents a valid email address format using the [Email Address Regular Expression That 99.99% Works](https://emailregex.com/)

```swift
extension String {
	var isValidEmailAddress: Bool {
		guard !isEmpty else { return false }
		let regex = #"(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")@(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])"#
		guard let match = range(of: regex, options: .regularExpression, range: nil, locale: nil) else { return false }
		let aCount = distance(from: match.lowerBound, to: match.upperBound)
		return aCount == count
	}
}
```

###### Usage example
```swift
[!copy]
"johnny@appleseed.com".isValidEmailAddress // true
"hello world".isValidEmailAddress // false
```

A simple extension to check if an email is in valid format using Regex

Validate email address format

Swift

Usage example