Convert CrytpoJS javascript to Swift 5 iOS with CryptoKit

Building HMAC authentication in iOS app to access an API. Successful requests can curently be made from Postman using javascript (CryptoJS). Here is the working Postman Pre-request code which needs to be converted to Swift using Apple's CryptoKit where applicable.


function interpolate (value) {
const {Property} = require('postman-collection');
return Property.replaceSubstitutions(value, pm.variables.toObject());
}

var uuid = require('uuid');
var moment = require("moment")

var hmacPrefix = "hmac";
var AppId = "add-some-id-string-here";
var APIKey = "add-some-key-here";

var requestURI = encodeURIComponent(pm.environment.values.substitute(pm.request.url, null, false).toString().toLowerCase());//Will set manually in swift. needs to be URL encoded

var requestMethod = pm.request.method; //Can set manually in Swift to 'post'

var requestTimeStamp = moment(new Date().toUTCString()).valueOf() / 1000;
var nonce = uuid.v4();
var requestContentBase64String = "";
var bodyString = interpolate(pm.request.body.toString());

if (bodyString) {
var md5 = CryptoJS.MD5(bodyString);
requestContentBase64String = CryptoJS.enc.Base64.stringify(md5);
}

var signatureRawData = AppId + requestMethod + requestURI + requestTimeStamp + nonce + requestContentBase64String; //check
var signature = CryptoJS.enc.Utf8.parse(signatureRawData);
var secretByteArray = CryptoJS.enc.Base64.parse(APIKey);
var signatureBytes = CryptoJS.HmacSHA256(signature,secretByteArray);
var requestSignatureBase64String = CryptoJS.enc.Base64.stringify(signatureBytes);

var hmacKey = hmacPrefix + " " + AppId + ":" + requestSignatureBase64String + ":" + nonce + ":" + requestTimeStamp;