A Swift extension class for String

StringExtension.swift

import Foundation


extension String {
  
  /* 
   * split a string into n lines
   * Eg: var s: String = "This is the first line.\nThis is the second line"
   * print(s.lines[0]) -> This is the first line
   */
    var lines: [String] {
        var result: [String] = []
        enumerateLines { line, _ in result.append(line) }
        return result
    }
    
  /* 
   * check if a string is empty
   * Eg: var s: String = ""
   * print(s.isEmptyStr) -> true
   */  
    var isEmptyStr:Bool {
        return self.trimmingCharacters(in: NSCharacterSet.whitespaces).isEmpty
    }
    
  
  /* 
   * check if a string is equal to another string
   * Eg: var s1: String = "string1"
   * var s2: String = "string2"
   * print(s1.isEqualToString(s2)) -> false
   */  
    func isEqualToString(find: String) -> Bool {
        return String(format: self) == find
    }
  
  
  /* 
   * convert a string to JSON
   */
    func toJSON() -> Any? {
        guard let data = self.data(using: .utf8, allowLossyConversion: false) else { return nil }
        return try? JSONSerialization.jsonObject(with: data, options: .mutableContainers)
    }
    
  
  /* 
   * get the index of a character in a string
   * Eg: var s:String = "This is a single sentence. This is another sentence."
   * let subString = s[s.indexOf(".")...] -> This will get the substring from the first index of '.' till the last index
   * print(subString) -> This is another sentence.
   */ 
    func indexOf(_ input: String,
                 options: String.CompareOptions = .literal) -> String.Index? {
        return self.range(of: input, options: options)?.lowerBound
    }
    

 
  /* 
   * get the last index of a character in a string
   * Eg: var s:String = "This is a single sentence. This is another sentence."
   * let subString = s[s.lastIndexOf(".")...] -> This will get the substring from the first index of '.' till the last index
   * print(subString) -> .
   */ 
    func lastIndexOf(_ input: String) -> String.Index? {
        return indexOf(input, options: .backwards)
    }
}