Pull out new throws

Author: jasnell

lib/buffer.js

@@ -47,14 +47,8 @@ function alignPool() {
 
 function Buffer(arg, encodingOrOffset, length) {
   // Common case.
-  if (typeof arg === 'number') {
-    if (typeof encodingOrOffset === 'string') {
-      throw new Error(
-        'If encoding is specified then the first argument must be a string'
-      );
-    }
+  if (typeof arg === 'number')
     return Buffer.allocUnsafe(arg);
-  }
   return Buffer.from(arg, encodingOrOffset, length);
 }
 
@@ -155,9 +149,6 @@ function fromString(string, encoding) {
   if (typeof encoding !== 'string' || encoding === '')
     encoding = 'utf8';
 
-  if (!Buffer.isEncoding(encoding))
-    throw new TypeError('"encoding" must be a valid string encoding');
-
   var length = byteLength(string, encoding);
   if (length >= (Buffer.poolSize >>> 1))
     return binding.createFromString(string, encoding);