ios - Cannot convert value of type NSAttributedString.DocumentAttributeKey to .DocumentReadingOptionKey -

i found string extension somewhere on internet allows me turn html code attributed string:

func html2attributedstring() -> nsattributedstring {     return try! nsattributedstring(data: self.data(using: string.encoding.unicode, allowlossyconversion: true)!, options: [nsdocumenttypedocumentattribute: nshtmltextdocumenttype], documentattributes: nil) } 

it worked fine in swift 3, swift 4, xcode complains:

cannot convert value of type 'nsattributedstring.documentattributekey' expected dictionary key type 'nsattributedstring.documentreadingoptionkey'

how fix this?

you need pass 1 of available nsattributedstring documenttype options:

---

hypertext markup language (html) document.

static let html: nsattributedstring.documenttype 

---

plain text document.

static let plain: nsattributedstring.documenttype 

---

rich text format document.

static let rtf: nsattributedstring.documenttype 

---

rich text format attachments document.

static let rtfd: nsattributedstring.documenttype 

---

in case need pass first 1 (html) nsattributedstring.documenttype.html

so extension updated swift 4 should this:

extension string {     var html2attributedstring: nsattributedstring? {         {             return try nsattributedstring(data: data(utf8),                                           options: [.documenttype: nsattributedstring.documenttype.html,                                                     .characterencoding: string.encoding.utf8.rawvalue],                                           documentattributes: nil)         } catch {             print("error: ", error)             return nil         }     }     var html2string: string {         return html2attributedstring?.string ?? ""     } }