I am using library with Xcode 10.2.1 (Swift 5), and found following code will throw Fatal error inside removeHTMLEntities
let jsonString = "{\"sepcialCharacter\": \"𝟸𝟺𝟶°\"}"
let json = try! JSONSerialization.jsonObject(with: jsonString.data(using: .utf8)!, options: []) as! [String:String]
let sepcialCharacter = json["sepcialCharacter"]!
sepcialCharacter.removingHTMLEntities
After investigation, seem this error may cause by NSString to swift String bridging with following code, not sure this is the bug in swift or the library itself
let nsSepcialCharacter = NSString("𝟸𝟺𝟶°")
let sepcialCharacter = nsSepcialCharacter as String
sepcialCharacter.removingHTMLEntities