docs: mi/466/hash-verification

Added Max's JS example for verifying the hash

docs/src/content/docs/introduction/hash-verification.mdx

@@ -44,6 +44,27 @@ x-gguKWTj8rQf7d7i3w3UhzvuJ5bpOlKyAlVpLxBffY
 
 When the client receives a redirect from the AS, the AS will include the hash parameter in the response. The client must calculate this exact value by concatenating the fields referenced above and then applying the `sha-256` hashing algorithm. If the hash value matches the parameter sent by the AS, then the client can be certain the redirect emanated from the AS.
 
+The example below demonstrates how to verify the hash received from the AS using a function in Javascript.
+
+<CodeBlock title="JavaScript example">
+
+```javascript
+function verifyHash(
+  clientNonce,
+  interactNonce,
+  interactRef,
+  authServerUrl,
+  receivedHash
+) {
+  const data = `${clientNonce}\n${interactNonce}\n${interactRef}\n${authServerUrl}/`
+  const hash = createHash('sha-256').update(data).digest('base64')
+
+  return hash === receivedHash
+}
+```
+
+</CodeBlock>
+
 ## Further reading
 
 For more information refer to the <LinkOut href='https://datatracker.ietf.org/doc/html/draft-ietf-gnap-core-protocol-20#name-calculating-the-interaction'>Calculating the interaction hash</LinkOut> section of the GNAP specification.