JSONDecoderFromStringLiteral.swift

import Foundation

// First one fails to be decoded.
//
// [1] dataCorrupted(Swift.DecodingError.Context(codingPath: [], debugDescription: "The given data was not valid JSON.", underlyingError: Optional(Error Domain=NSCocoaErrorDomain Code=3840 "Unescaped control character '0xa' around line 2, column 0." UserInfo={NSJSONSerializationErrorIndex=16, NSDebugDescription=Unescaped control character '0xa' around line 2, column 0.})))
// [2] Success!
//
// SeeAlso: https://github.com/apple/swift-evolution/blob/main/proposals/0200-raw-string-escaping.md

let literalJSONishString = """
{"message": "bbb\nccc" }
"""

let rawJSONString = #"""
{"message": "bbb\nccc" }
"""#

struct Response: Decodable {
    let message: String
}

do {
    _ = try JSONDecoder().decode(Response.self, from: literalJSONishString.data(using: .utf8)!)
    print("[1] Success!")
} catch {
    print("[1] \(error)")
}

do {
    _ = try JSONDecoder().decode(Response.self, from: rawJSONString.data(using: .utf8)!)
    print("[2] Success!")
} catch {
    print("[2] \(error)")
}