Creating HMAC in postman using CryptoJS

Place this script at pre-request-script and environment.secret is stored in environment variables or pass hardcoded here.
It will convert HMAC(.SHA256, /URI + /Body) and place into a global variable name as signature. which can pass on header like: x-pch-digest:{{signature}}

var index = request.url.indexOf('/');
var uri_path = request.url.substring(index);
var payload = uri_path + request.data;
console.log("Using payload as " + payload)
var hash = CryptoJS.HmacSHA256(payload, environment.secret);
var hashInBase64 = CryptoJS.enc.Hex.stringify(hash);
postman.setGlobalVariable("signature", hashInBase64);

See the images::