Is there a function to escape all regex-relevant characters?

Question

The regex I'm using in my application is a combination of user-input and code. Because I don't want to restrict the user I would like to escape all regex-relevant characters like "+", brackets , slashes etc. from the entry. Is there a function for that or at least an easy way to get all those characters in an array so that I can do something like this:

for regexChar in regexCharacterArray{
    myCombinedRegex = myCombinedRegex.replaceOccurences(of: regexChar, with: "\\" + regexChar)
}

Answer 1

Yes, there is NSRegularExpression.escapedPattern(for:):

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

Example:

let escaped = NSRegularExpression.escapedPattern(for: "[*]+")
print(escaped) // \[\*]\+