buffer: throw on invalid encoding in Buffer.from

Refs: #54533
PR-URL: #54586

Author: ronag

lib/buffer.js

@@ -476,7 +476,7 @@ function createFromString(string, ops, length = ops.byteLength(string)) {
 
 function fromString(string, encoding) {
   let ops;
-  if (!encoding || encoding === 'utf8' || typeof encoding !== 'string') {
+  if (encoding == null || encoding === 'utf8') {
     ops = encodingOps.utf8;
   } else {
     ops = getEncodingOps(encoding);

test/parallel/test-buffer-from.js

@@ -140,5 +140,8 @@ throws(() => {
   })
 );
 
-// Invalid encoding is allowed
-Buffer.from('asd', 1);
+throws(() => {
+  Buffer.from('asd', 1);
+}, {
+  code: 'ERR_UNKNOWN_ENCODING'
+});