How to avoid an error due to special characters in search string when using Regex for a simple search in Swift?

Question

I\'m using Regex to search for a word in a textView. I implemented a textField and two switch as options (Whole words and Match case). All work fine when you enter a plain word

Answer 1

You may use NSRegularExpression.escapedPatternForString:

Returns a string by adding backslash escapes as necessary to protect any characters that would match as pattern metacharacters.

Thus, you need

var pattern = NSRegularExpression.escapedPatternForString(searchString)

Also, note that this piece:

if isWholeWords {
    pattern = "\\b\(searchString)\\b"

might fail if a user inputs (text) and wishes to search for it as a whole word. The best way to match whole words is by means of lookarounds disallowing word chars on both ends of the search word:

if isWholeWords {
    pattern = "(?<!\\w)" + NSRegularExpression.escapedPatternForString(searchString) + "(?!\\w)"