1 files changed, 11 insertions, 14 deletions

diff --git a/lib/_stream_writable.js b/lib/_stream_writable.js
index cada467f74..a6b02f6c2a 100644
--- a/lib/_stream_writable.js
+++ b/lib/_stream_writable.js
@@ -153,10 +153,9 @@ function writeAfterEnd(stream, state, cb) {
 // how many bytes or characters.
 function validChunk(stream, state, chunk, cb) {
   var valid = true;
-  if (!Buffer.isBuffer(chunk) &&
-      'string' !== typeof chunk &&
-      chunk !== null &&
-      chunk !== undefined &&
+  if (!IS_BUFFER(chunk) &&
+      !IS_STRING(chunk) &&
+      !IS_NULL_OR_UNDEFINED(chunk) &&
       !state.objectMode) {
     var er = new TypeError('Invalid non-string/buffer chunk');
     stream.emit('error', er);
@@ -172,17 +171,17 @@ Writable.prototype.write = function(chunk, encoding, cb) {
   var state = this._writableState;
   var ret = false;
 
-  if (typeof encoding === 'function') {
+  if (IS_FUNCTION(encoding)) {
     cb = encoding;
     encoding = null;
   }
 
-  if (Buffer.isBuffer(chunk))
+  if (IS_BUFFER(chunk))
     encoding = 'buffer';
   else if (!encoding)
     encoding = state.defaultEncoding;
 
-  if (typeof cb !== 'function')
+  if (!IS_FUNCTION(cb))
     cb = function() {};
 
   if (state.ended)
@@ -217,9 +216,7 @@ Writable.prototype.uncork = function() {
 };
 
 function decodeChunk(state, chunk, encoding) {
-  if (!state.objectMode &&
-      state.decodeStrings !== false &&
-      typeof chunk === 'string') {
+  if (!state.objectMode && state.decodeStrings !== false && IS_STRING(chunk)) {
     chunk = new Buffer(chunk, encoding);
   }
   return chunk;
@@ -230,7 +227,7 @@ function decodeChunk(state, chunk, encoding) {
 // If we return false, then we need a drain event, so set that flag.
 function writeOrBuffer(stream, state, chunk, encoding, cb) {
   chunk = decodeChunk(state, chunk, encoding);
-  if (Buffer.isBuffer(chunk))
+  if (IS_BUFFER(chunk))
     encoding = 'buffer';
   var len = state.objectMode ? 1 : chunk.length;
 
@@ -391,16 +388,16 @@ Writable.prototype._writev = null;
 Writable.prototype.end = function(chunk, encoding, cb) {
   var state = this._writableState;
 
-  if (typeof chunk === 'function') {
+  if (IS_FUNCTION(chunk)) {
     cb = chunk;
     chunk = null;
     encoding = null;
-  } else if (typeof encoding === 'function') {
+  } else if (IS_FUNCTION(encoding)) {
     cb = encoding;
     encoding = null;
   }
 
-  if (typeof chunk !== 'undefined' && chunk !== null)
+  if (!IS_NULL_OR_UNDEFINED(chunk))
     this.write(chunk, encoding);
 
   // .end() fully uncorks