UniquieMap

uniquiemap.swift

public func uniqueMap<T: Equatable>(_ transform: (Iterator.Element) throws -> T) rethrows -> [T] {

        let count: Int = numericCast(self.count)
        if isEmpty {
            return []
        }

        var result = ContiguousArray<T>()
        result.reserveCapacity(count)

        var i = self.startIndex

        for _ in 0..<count {
            let transformed = try transform(self[i])
            if !result.contains(where: { $0 == transformed }) {
                result.append(transformed)
            }
            formIndex(after: &i)
        }
        return Array(result)
    }