[SOLVED] How to convert `Date` to `Data`, and vice versa in Swift 5?

How to convert `Date` to `Data`, and vice versa in Swift 5?

I'm trying to save a date in Keychain, and (from my understanding) this first requires converting the Date object into a Data object.

This Stack Overflow Q/A explains how to do it (or at least part of it) in Swift 3, but I'm hoping someone can provide the to/from functions in Swift 5 (since at least one of the methods in that solution are deprecated and I'm worried something else hasn't stood the test of time either).

Solution

A Date is a juste a Timestamp (number of seconds since reference date of 1970 at UTC) as an object with fancy methods and other utilities. That's nothing more.

So based on the answer Double to Data (and reverse):

Input

let date = Date()
print(date)

Date -> Timestamp -> Data

let timestamp = date.timeIntervalSinceReferenceDate
print(timestamp)
let data = withUnsafeBytes(of: timestamp) { Data($0) }
print("\(data) - \(data.map{ String(format: "%02hhx", $0) }.joined())")

Data -> Timestamp -> Date

let retrievedTimestamp = data.withUnsafeBytes { $0.load(as: Double.self) }
print(retrievedTimestamp)
let retrievedDate = Date(timeIntervalSinceReferenceDate: retrievedTimestamp)
print(retrievedDate)

Output:

$>2021-09-13 08:17:50 +0000
$>1631521070.6852288
$>8 bytes - cadaab4bc24fd841
$>1631521070.6852288
$>2021-09-13 08:17:50 +0000