stream: simplify Writable.write

Slightly refactors Writable.write for minor perf
and readability improvements.

PR-URL: #31146
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: David Carlier <devnexen@gmail.com>

lib/_stream_writable.js

@@ -270,12 +270,6 @@ Writable.prototype.pipe = function() {
 
 Writable.prototype.write = function(chunk, encoding, cb) {
   const state = this._writableState;
-  const isBuf = !state.objectMode && Stream._isUint8Array(chunk);
-
-  // Do not use Object.getPrototypeOf as it is slower since V8 7.3.
-  if (isBuf && !(chunk instanceof Buffer)) {
-    chunk = Stream._uint8ArrayToBuffer(chunk);
-  }
 
   if (typeof encoding === 'function') {
     cb = encoding;
@@ -287,34 +281,38 @@ Writable.prototype.write = function(chunk, encoding, cb) {
       cb = nop;
   }
 
-  if (isBuf)
-    encoding = 'buffer';
-
   let err;
   if (state.ending) {
     err = new ERR_STREAM_WRITE_AFTER_END();
   } else if (state.destroyed) {
     err = new ERR_STREAM_DESTROYED('write');
   } else if (chunk === null) {
     err = new ERR_STREAM_NULL_VALUES();
-  } else {
-    if (!isBuf && !state.objectMode) {
-      if (typeof chunk !== 'string') {
-        err = new ERR_INVALID_ARG_TYPE('chunk', ['string', 'Buffer'], chunk);
-      } else if (encoding !== 'buffer' && state.decodeStrings !== false) {
+  } else if (!state.objectMode) {
+    if (typeof chunk === 'string') {
+      if (state.decodeStrings !== false) {
         chunk = Buffer.from(chunk, encoding);
         encoding = 'buffer';
       }
-    }
-    if (err === undefined) {
-      state.pendingcb++;
-      return writeOrBuffer(this, state, chunk, encoding, cb);
+    } else if (chunk instanceof Buffer) {
+      encoding = 'buffer';
+    } else if (Stream._isUint8Array(chunk)) {
+      chunk = Stream._uint8ArrayToBuffer(chunk);
+      encoding = 'buffer';
+    } else {
+      err = new ERR_INVALID_ARG_TYPE(
+        'chunk', ['string', 'Buffer', 'Uint8Array'], chunk);
     }
   }
 
-  process.nextTick(cb, err);
-  errorOrDestroy(this, err, true);
-  return false;
+  if (err) {
+    process.nextTick(cb, err);
+    errorOrDestroy(this, err, true);
+    return false;
+  } else {
+    state.pendingcb++;
+    return writeOrBuffer(this, state, chunk, encoding, cb);
+  }
 };
 
 Writable.prototype.cork = function() {

test/parallel/test-net-write-arguments.js

@@ -29,6 +29,6 @@ assert.throws(() => socket.write(null),
     code: 'ERR_INVALID_ARG_TYPE',
     name: 'TypeError',
     message: 'The "chunk" argument must be of type string or an instance of ' +
-              `Buffer.${common.invalidArgTypeHelper(value)}`
+              `Buffer or Uint8Array.${common.invalidArgTypeHelper(value)}`
   }));
 });