Improve secretOrKey initialization in VerifyStream

Refactor secretOrKey assignment logic for clarity.

Author: panva

lib/verify-stream.js

@@ -79,7 +79,12 @@ function jwsDecode(jwsSig, opts) {
 
 function VerifyStream(opts) {
   opts = opts || {};
-  var secretOrKey = opts.secret||opts.publicKey||opts.key;
+  var secretOrKey = opts.secret;
+  secretOrKey = secretOrKey == null ? opts.publicKey : secretOrKey;
+  secretOrKey = secretOrKey == null ? opts.key : secretOrKey;
+  if (/^hs/i.test(opts.algorithm) === true && secretOrKey == null) {
+    throw new TypeError('secret must be a string or buffer or a KeyObject')
+  }
   var secretStream = new DataStream(secretOrKey);
   this.readable = true;
   this.algorithm = opts.algorithm;