azure-app-configuration-pre-request.js

var credential = "YOUR-APP-CONFIGURATION-CREDENTIAL-ID";
var secret = "YOUR-APP-CONFIGURATION-CREDENTIAL-VALUE";

function signRequest(host, 
                     method,      // GET, PUT, POST, DELETE
                     url,         // path+query
                     body,        // request body (undefined of none)
                     credential,  // access key id
                     secret)      // access key value (base64 encoded)
{
        var verb = method.toUpperCase();
        var utcNow = new Date().toUTCString();
        var contentHash = CryptoJS.SHA256(body).toString(CryptoJS.enc.Base64);

        //
        // SignedHeaders
        var signedHeaders = "x-ms-date;host;x-ms-content-sha256"; // Semicolon separated header names

        //
        // String-To-Sign
        var stringToSign = 
            verb + '\n' +                              // VERB
            url + '\n' +                               // path_and_query
            utcNow + ';' + host + ';' + contentHash;   // Semicolon separated SignedHeaders values

        //
        // Signature
        var signature = CryptoJS.HmacSHA256(stringToSign, CryptoJS.enc.Base64.parse(secret)).toString(CryptoJS.enc.Base64);

        //
        // Result request headers
        return [
            { name: "x-ms-date", value: utcNow },
            { name: "x-ms-content-sha256", value: contentHash },
            { name: "Authorization", value: "HMAC-SHA256 Credential=" + credential + "&SignedHeaders=" + signedHeaders + "&Signature=" + signature }
        ];
}

var isBodyEmpty = pm.request.body === null || pm.request.body === undefined || pm.request.body.isEmpty();

var headers = signRequest(
    pm.request.url.getHost(),
    pm.request.method,
    pm.request.url.getPathWithQuery(),
    isBodyEmpty ? undefined : pm.request.body.toString(),
    credential,
    secret);

// Add headers to the request
headers.forEach(header => {
    pm.request.headers.upsert({key: header.name, value: header.value});
})