tls: simplify getCACertificates() structure per review

Author: haramj

lib/tls.js

@@ -202,40 +202,36 @@ function getCACertificatesAsStrings(type = 'default') {
 }
 
 function getCACertificates(options = undefined) {
-  if (typeof options === 'string' || options === undefined) {
-    return getCACertificatesAsStrings(options);
-  }
+  let type = 'default';
+  let format = 'pem';
 
   if (typeof options === 'object' && options !== null) {
-    const {
-      type = 'default',
-      format = 'pem',
-    } = options;
-
-    validateString(type, 'type');
-    validateOneOf(format, 'format', ['pem', 'der', 'x509', 'string', 'buffer']);
+    ({ type = 'default', format = 'pem' } = options);
+  } else if (typeof options === 'string' || options === undefined) {
+    type = options ?? 'default';
+  } else {
+    throw new ERR_INVALID_ARG_TYPE('options', ['string', 'object'], options);
+  }
 
-    const certs = getCACertificatesAsStrings(type);
+  validateString(type, 'type');
+  validateOneOf(format, 'format', ['pem', 'der', 'x509', 'string', 'buffer']);
 
-    if (format === 'x509') {
-      return certs.map((cert) => new X509Certificate(cert));
-    }
+  const certs = getCACertificatesAsStrings(type);
 
-    if (format === 'pem' || format === 'string') {
-      return certs;
-    }
-
-    const buffers = certs.map((cert) => {
-      const base64 = cert.replace(/(?:\s|-----BEGIN CERTIFICATE-----|-----END CERTIFICATE-----)+/g, '');
-      return Buffer.from(base64, 'base64');
-    });
+  if (format === 'pem' || format === 'string') {
+    return certs;
+  }
 
-    if (format === 'der' || format === 'buffer') {
-      return buffers;
-    }
+  if (format === 'x509') {
+    return certs.map((cert) => new X509Certificate(cert));
   }
 
-  throw new ERR_INVALID_ARG_TYPE('options', ['string', 'object'], options);
+  const buffers = certs.map((cert) => {
+    const base64 = cert.replace(/(?:\s|-----BEGIN CERTIFICATE-----|-----END CERTIFICATE-----)+/g, '');
+    return Buffer.from(base64, 'base64');
+  });
+
+  return buffers;
 }
 
 exports.getCACertificates = getCACertificates;