StringChomp.swift

extension String {
    
    func removingPossibleSuffix(_ suffix: String) -> String {
        guard hasSuffix(suffix) else {
            return self
        }
        var segments = components(separatedBy: suffix)
        if segments.count > 1 {
            segments.removeLast()
            return segments.joined(separator: suffix)
        }
        else {
            return segments.first ?? ""
        }
    }
    
    func removingPossibleSuffixes(_ suffixes: Set<String>) -> String {
        guard !suffixes.isEmpty else {
            return self
        }
        
        let suffixSubstrings = suffixes.filter { self.contains($0) }
        guard !suffixSubstrings.isEmpty else {
            return self
        }
        
        var output = self
        for suffix in suffixSubstrings {
            output = output.removingPossibleSuffix(suffix)
        }
        
        if output == self {
            return self
        }
        return output.removingPossibleSuffixes(suffixSubstrings)
    }
    
}

// EXAMPLES:

let screenName1 = "MyStupidViewController"
print(screenName1.removingPossibleSuffix("ViewController"))
// returns "MyStupid"

let screenName2 = "MyStupidVC"
print(screenName2.removingPossibleSuffix("VC"))
// returns "MyStupid"

let screenName3 = "MyStupidVC"
print(screenName3.removingPossibleSuffix("Fart"))
// returns "MyStupidVC"

let screenName4 = "MyStupidVCViewControllerVCViewController"
print(screenName4.removingPossibleSuffixes(["ViewController", "VC", "Fart"]))
// returns "MyStupid"