vicc

extension String {
    /**
     Truncates the string to the specified length number of characters and appends an optional trailing string if longer.
     
     - Parameter length: A `String`.
     - Parameter trailing: A `String` that will be appended after the truncation.
    
     - Returns: A `String` object. 
     */
    func truncate(length: Int, trailing: String = "…") -> String {

mikelehen

/**
 * Fancy ID generator that creates 20-character string identifiers with the following properties:
 *
 * 1. They're based on timestamp so that they sort *after* any existing ids.
 * 2. They contain 72-bits of random data after the timestamp so that IDs won't collide with other clients' IDs.
 * 3. They sort *lexicographically* (so the timestamp is converted to characters that will sort properly).
 * 4. They're monotonically increasing.  Even if you generate more than one in the same timestamp, the
 *    latter ones will sort after the former ones.  We do this by using the previous random bits
 *    but "incrementing" them by 1 (only in the case of a timestamp collision).
 */