Extensions for Swift's String Type

StringExtensions.swift

extension String {

    /// Usage: "Hello World".until(" World") --> "Hello"
    mutating func until(_ string: String) {
        var components = self.components(separatedBy: string)
        self = components[0]
    }
    
    /// Blows a string up to totalLength by pre- and postfixing characters (e.g. "hello".withAddedDivider("-", totalLength: 13) returns "--- hello ---")
    func withAddedDivider(_ divider: Character, totalLength: Int, padding: Int = 1) -> String {
        let contentLength = self.count + 2 * padding
        guard contentLength < totalLength else { return self }
        let dividerLength = totalLength - contentLength
        let oddLength = (totalLength - contentLength) % 2 > 0
        let halfDivider = String.init(repeating: divider, count: dividerLength / 2)
        let spacing = String.init(repeating: " ", count: padding)
        let oddLengthFix = oddLength ? "\(divider)" : ""
        return "\(halfDivider)\(spacing)\(self)\(spacing)\(halfDivider)\(oddLengthFix)"
    }

}