[perf] Micro optimisations (#84)

lib/index.js

@@ -83,11 +83,11 @@ exports.encodePacket = function (packet, supportsBinary, utf8encode, callback) {
  */
 
 function encodeBuffer(packet, supportsBinary, callback) {
-  var data = packet.data;
   if (!supportsBinary) {
     return exports.encodeBase64Packet(packet, callback);
   }
 
+  var data = packet.data;
   var typeBuffer = new Buffer(1);
   typeBuffer[0] = packets[packet.type];
   return callback(Buffer.concat([typeBuffer, data]));
@@ -121,14 +121,18 @@ exports.decodePacket = function (data, binaryType, utf8decode) {
   if (data === undefined) {
     return err;
   }
+
+  var type;
+
   // String data
   if (typeof data === 'string') {
-    if (data.charAt(0) === 'b') {
+
+    type = data.charAt(0);
+
+    if (type === 'b') {
       return exports.decodeBase64Packet(data.substr(1), binaryType);
     }
 
-    var type = data.charAt(0);
-
     if (utf8decode) {
       data = tryDecode(data);
       if (data === false) {
@@ -151,14 +155,14 @@ exports.decodePacket = function (data, binaryType, utf8decode) {
   if (binaryType === 'arraybuffer') {
     // wrap Buffer/ArrayBuffer data into an Uint8Array
     var intArray = new Uint8Array(data);
-    var type = intArray[0];
+    type = intArray[0];
     return { type: packetslist[type], data: intArray.buffer.slice(1) };
   }
 
   if (data instanceof ArrayBuffer) {
     data = arrayBufferToBuffer(data);
   }
-  var type = data[0];
+  type = data[0];
   return { type: packetslist[type], data: data.slice(1) };
 };
 
@@ -221,10 +225,6 @@ exports.encodePayload = function (packets, supportsBinary, callback) {
     return callback('0:');
   }
 
-  function setLengthHeader(message) {
-    return message.length + ':' + message;
-  }
-
   function encodeOne(packet, doneCallback) {
     exports.encodePacket(packet, supportsBinary, false, function(message) {
       doneCallback(null, setLengthHeader(message));
@@ -236,6 +236,10 @@ exports.encodePayload = function (packets, supportsBinary, callback) {
   });
 };
 
+function setLengthHeader(message) {
+  return message.length + ':' + message;
+}
+
 /**
  * Async array map using after
  */
@@ -244,15 +248,11 @@ function map(ary, each, done) {
   var result = new Array(ary.length);
   var next = after(ary.length, done);
 
-  var eachWithIndex = function(i, el, cb) {
-    each(el, function(error, msg) {
+  for (var i = 0; i < ary.length; i++) {
+    each(ary[i], function(error, msg) {
       result[i] = msg;
-      cb(error, result);
+      next(error, result);
     });
-  };
-
-  for (var i = 0; i < ary.length; i++) {
-    eachWithIndex(i, ary[i], next);
   }
 }
 
@@ -274,13 +274,12 @@ exports.decodePayload = function (data, binaryType, callback) {
     binaryType = null;
   }
 
-  var packet;
   if (data === '') {
     // parser error - ignoring payload
     return callback(err, 0, 1);
   }
 
-  var length = '', n, msg;
+  var length = '', n, msg, packet;
 
   for (var i = 0, l = data.length; i < l; i++) {
     var chr = data.charAt(i);
@@ -310,8 +309,8 @@ exports.decodePayload = function (data, binaryType, callback) {
         return callback(err, 0, 1);
       }
 
-      var ret = callback(packet, i + n, l);
-      if (false === ret) return;
+      var more = callback(packet, i + n, l);
+      if (false === more) return;
     }
 
     // advance cursor
@@ -395,35 +394,42 @@ exports.encodePayloadAsBinary = function (packets, callback) {
     return callback(new Buffer(0));
   }
 
-  function encodeOne(p, doneCallback) {
-    exports.encodePacket(p, true, true, function(packet) {
-
-      if (typeof packet === 'string') {
-        var encodingLength = '' + packet.length;
-        var sizeBuffer = new Buffer(encodingLength.length + 2);
-        sizeBuffer[0] = 0; // is a string (not true binary = 0)
-        for (var i = 0; i < encodingLength.length; i++) {
-          sizeBuffer[i + 1] = parseInt(encodingLength[i], 10);
-        }
-        sizeBuffer[sizeBuffer.length - 1] = 255;
-        return doneCallback(null, Buffer.concat([sizeBuffer, stringToBuffer(packet)]));
-      }
+  map(packets, encodeOneBinaryPacket, function(err, results) {
+    return callback(Buffer.concat(results));
+  });
+};
 
-      var encodingLength = '' + packet.length;
-      var sizeBuffer = new Buffer(encodingLength.length + 2);
-      sizeBuffer[0] = 1; // is binary (true binary = 1)
+function encodeOneBinaryPacket(p, doneCallback) {
+
+  function onBinaryPacketEncode(packet) {
+
+    var encodingLength = '' + packet.length;
+    var sizeBuffer;
+
+    if (typeof packet === 'string') {
+      sizeBuffer = new Buffer(encodingLength.length + 2);
+      sizeBuffer[0] = 0; // is a string (not true binary = 0)
       for (var i = 0; i < encodingLength.length; i++) {
         sizeBuffer[i + 1] = parseInt(encodingLength[i], 10);
       }
       sizeBuffer[sizeBuffer.length - 1] = 255;
-      doneCallback(null, Buffer.concat([sizeBuffer, packet]));
-    });
+      return doneCallback(null, Buffer.concat([sizeBuffer, stringToBuffer(packet)]));
+    }
+
+    sizeBuffer = new Buffer(encodingLength.length + 2);
+    sizeBuffer[0] = 1; // is binary (true binary = 1)
+    for (var i = 0; i < encodingLength.length; i++) {
+      sizeBuffer[i + 1] = parseInt(encodingLength[i], 10);
+    }
+    sizeBuffer[sizeBuffer.length - 1] = 255;
+
+    doneCallback(null, Buffer.concat([sizeBuffer, packet]));
   }
 
-  map(packets, encodeOne, function(err, results) {
-    return callback(Buffer.concat(results));
-  });
-};
+  exports.encodePacket(p, true, true, onBinaryPacketEncode);
+
+}
+
 
 /*
  * Decodes data when a payload is maybe expected. Strings are decoded by
@@ -442,11 +448,12 @@ exports.decodePayloadAsBinary = function (data, binaryType, callback) {
 
   var bufferTail = data;
   var buffers = [];
+  var i;
 
   while (bufferTail.length > 0) {
     var strLen = '';
     var isString = bufferTail[0] === 0;
-    for (var i = 1; ; i++) {
+    for (i = 1; ; i++) {
       if (bufferTail[i] === 255)  break;
       // 310 = char length of Number.MAX_VALUE
       if (strLen.length > 310) {
@@ -465,7 +472,8 @@ exports.decodePayloadAsBinary = function (data, binaryType, callback) {
   }
 
   var total = buffers.length;
-  buffers.forEach(function(buffer, i) {
+  for (i = 0; i < total; i++) {
+    var buffer = buffers[i];
     callback(exports.decodePacket(buffer, binaryType, true), i, total);
-  });
+  }
 };