How to use OR for a value that can be nil?-CodePudding

This is very basic but I'm kinda confused why my code isn't working. I have a user that has an optional username and I am trying to check whether the email or username contains my search query

struct ChatUser: Codable, Identifiable {
let email: String    
var username: String?
}

@State var user: ChatUser

if user.email.lowercased().contains(search.lowercased()) || 
user.username.lowercased().contains(search.lowercased()) {...}

It works if I unwrap user.username! but then my App crashes due to unwrapping nil values. How do I check for user.username != nil and then force unwrap in the if check?

CodePudding user response：

Calling lowercased() again and again is unnecessarily expensive.

But with your given syntax this is the swifty way

if user.email.lowercased().contains(search.lowercased()) || 
   user.username?.lowercased().contains(search.lowercased()) == true {...}

The Optional Chaining expression returns nil immediately if username is nil.

However range(of:options: can handle the optional and the case

if user.email.range(of: search, options: .caseInsensitive) != nil ||
    user.username?.range(of: search, options: .caseInsensitive) != nil {

}

CodePudding user response：

You can use nil-coalescing(??) to unwrap your optional value.

if user.email.lowercased().contains(search.lowercased()) || 
user.username?.lowercased().contains(search.lowercased()) ?? false {

}

CodePudding user response：

if user.email.lowercased().contains(search.lowercased()) || 
(user.username.map { $0.lowercased().contains(search.lowercased()) } ?? false) {

}