diff --git a/.eslintrc b/.eslintrc
index 5028354..3cb7332 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -107,7 +107,7 @@
         "arrow-spacing": 1,
         "accessor-pairs": 1,
         "block-scoped-var": 0,
-        "brace-style": [1, "1tbs"],
+        "brace-style": [1, "stroustrup"],
         "callback-return": [2, ["callback", "cb", "next"]],
         "camelcase": [2, {"properties": "always"}],
         "comma-dangle": [2, "never"],
@@ -129,7 +129,7 @@
         "generator-star-spacing": 0,
         "guard-for-in": 1,
         "handle-callback-err": 2,
-        "id-length": [2, {"min": 3, "max": 20, "exceptions":["x", "y", "i", "j"]}],
+        "id-length": [2, {"min": 3, "max": 20, "exceptions":["x", "y", "i", "j", "ex", "up"]}],
         "indent": [1, 2, {"SwitchCase": 1}],
         "init-declarations": 0,
         "key-spacing": [1, { "beforeColon": false, "afterColon": true }],
diff --git a/lib/bitmapper.js b/lib/bitmapper.js
index 2810302..217da6a 100644
--- a/lib/bitmapper.js
+++ b/lib/bitmapper.js
@@ -104,7 +104,8 @@ exports.dataToBitMap = function(data, width, height, bpp, depth, interlace) {
   var pxData;
   if (depth <= 8) {
     pxData = new Buffer(width * height * 4);
-  } else {
+  }
+  else {
     pxData = new Uint16Array(width * height * 4);
   }
   var maxBit = Math.pow(2, depth) - 1;
@@ -116,7 +117,8 @@ exports.dataToBitMap = function(data, width, height, bpp, depth, interlace) {
   if (interlace) {
     images = interlaceUtils.getImagePasses(width, height);
     getPxPos = interlaceUtils.getInterlaceIterator(width, height);
-  } else {
+  }
+  else {
     var nonInterlacedPxPos = 0;
     getPxPos = function() {
       var returner = nonInterlacedPxPos;
@@ -144,7 +146,8 @@ exports.dataToBitMap = function(data, width, height, bpp, depth, interlace) {
               throw new Error('Ran out of data');
             }
             pxData[pxPos + i] = idx !== 0xff ? data[idx + rawPos] : maxBit;
-          } else {
+          }
+          else {
             pxData[pxPos + i] = idx !== 0xff ? pixelData[idx] : maxBit;
           }
         }
@@ -160,7 +163,8 @@ exports.dataToBitMap = function(data, width, height, bpp, depth, interlace) {
     if (rawPos !== data.length) {
       throw new Error('extra data found');
     }
-  } else {
+  }
+  else {
     bits.end();
   }
 
diff --git a/lib/chunkstream.js b/lib/chunkstream.js
index f6e8939..3139e4f 100755
--- a/lib/chunkstream.js
+++ b/lib/chunkstream.js
@@ -70,7 +70,8 @@ ChunkStream.prototype.write = function(data, encoding) {
   var dataBuffer;
   if (Buffer.isBuffer(data)) {
     dataBuffer = data;
-  } else {
+  }
+  else {
     dataBuffer = new Buffer(data, encoding || this._encoding);
   }
 
@@ -80,7 +81,7 @@ ChunkStream.prototype.write = function(data, encoding) {
   this._process();
 
   // ok if there are no more read requests
-  if (this._reads && this._reads.length == 0) {
+  if (this._reads && this._reads.length === 0) {
     this._paused = true;
   }
 
@@ -96,12 +97,15 @@ ChunkStream.prototype.end = function(data, encoding) {
   this.writable = false;
 
   // already destroyed
-  if (!this._buffers) return;
+  if (!this._buffers) {
+    return;
+  }
 
   // enqueue or handle end
-  if (this._buffers.length == 0) {
+  if (this._buffers.length === 0) {
     this._end();
-  } else {
+  }
+  else {
     this._buffers.push(null);
     this._process();
   }
@@ -157,7 +161,8 @@ ChunkStream.prototype._process = function() {
 
         read.func.call(this, smallerBuf.slice(0, read.length));
 
-      } else {
+      }
+      else {
         // ok this is less than maximum length so use it all
         this._buffered -= smallerBuf.length;
         this._buffers.shift(); // == smallerBuf
@@ -165,7 +170,8 @@ ChunkStream.prototype._process = function() {
         read.func.call(this, smallerBuf);
       }
 
-    } else if (this._buffered >= read.length) {
+    }
+    else if (this._buffered >= read.length) {
       // ok we can meet some expectations
 
       this._reads.shift(); // == read
@@ -184,19 +190,22 @@ ChunkStream.prototype._process = function() {
         pos += len;
 
         // last buffer wasn't used all so just slice it and leave
-        if (len != buf.length)
+        if (len !== buf.length) {
           this._buffers[--count] = buf.slice(len);
+        }
       }
 
       // remove all used buffers
-      if (count > 0)
+      if (count > 0) {
         this._buffers.splice(0, count);
+      }
 
       this._buffered -= read.length;
 
       read.func.call(this, data);
 
-    } else {
+    }
+    else {
       // not enought data to satisfy first request in queue
       // so we need to wait for more
       break;
diff --git a/lib/constants.js b/lib/constants.js
index d97fc03..3b496ba 100755
--- a/lib/constants.js
+++ b/lib/constants.js
@@ -29,10 +29,8 @@ module.exports = {
   TYPE_IEND: 0x49454e44,
   TYPE_IDAT: 0x49444154,
   TYPE_PLTE: 0x504c5445,
-  /*eslint camelcase: 0*/
-  TYPE_tRNS: 0x74524e53,
-  TYPE_gAMA: 0x67414d41,
-  /*eslint camelcase: 1*/
+  TYPE_tRNS: 0x74524e53, // eslint-disable-line camelcase
+  TYPE_gAMA: 0x67414d41, // eslint-disable-line camelcase
 
   COLOR_PALETTE: 1,
   COLOR_COLOR: 2,
diff --git a/lib/crc.js b/lib/crc.js
index 9859237..8701fcb 100755
--- a/lib/crc.js
+++ b/lib/crc.js
@@ -28,7 +28,8 @@ var crcTable = [];
     for (var j = 0; j < 8; j++) {
       if (currentCrc & 1) {
         currentCrc = 0xedb88320 ^ (currentCrc >>> 1);
-      } else {
+      }
+      else {
         currentCrc = currentCrc >>> 1;
       }
     }
diff --git a/lib/filter-async.js b/lib/filter-async.js
index 4d05eff..15ff459 100644
--- a/lib/filter-async.js
+++ b/lib/filter-async.js
@@ -33,7 +33,7 @@ var FilterAsync = module.exports = function(width, height, Bpp, depth, interlace
   this._filter = new Filter(width, height, Bpp, depth, interlace, options, {
     read: this.read.bind(this),
     complete: function() {
-      that.emit('complete', Buffer.concat(buffers), width, height)
+      that.emit('complete', Buffer.concat(buffers), width, height);
     },
     write: function(buffer) {
       buffers.push(buffer);
diff --git a/lib/filter.js b/lib/filter.js
index cd8a12f..ee73810 100755
--- a/lib/filter.js
+++ b/lib/filter.js
@@ -30,12 +30,12 @@ function getByteWidth(width, bpp, depth) {
   return byteWidth;
 }
 
-function PaethPredictor(left, above, upLeft) {
+function paethPredictor(left, above, upLeft) {
 
-  var p = left + above - upLeft,
-    pLeft = Math.abs(p - left),
-    pAbove = Math.abs(p - above),
-    pUpLeft = Math.abs(p - upLeft);
+  var paeth = left + above - upLeft;
+  var pLeft = Math.abs(paeth - left);
+  var pAbove = Math.abs(paeth - above);
+  var pUpLeft = Math.abs(paeth - upLeft);
 
   if (pLeft <= pAbove && pLeft <= pUpLeft) {
     return left;
@@ -51,13 +51,14 @@ var Filter = module.exports = function(width, height, Bpp, depth, interlace, opt
 
   this._width = width;
   this._height = height;
-  this._Bpp = Bpp;
+  this._Bpp = Bpp; //TODO rename
   this._depth = depth;
   this._options = options;
 
-  if (!('filterType' in options) || options.filterType == -1) {
+  if (!('filterType' in options) || options.filterType === -1) {
     options.filterType = [0, 1, 2, 3, 4];
-  } else if (typeof options.filterType == 'number') {
+  }
+  else if (typeof options.filterType === 'number') {
     options.filterType = [options.filterType];
   }
 
@@ -84,7 +85,8 @@ var Filter = module.exports = function(width, height, Bpp, depth, interlace, opt
         lineIndex: 0
       });
     }
-  } else {
+  }
+  else {
     this._images.push({
       byteWidth: getByteWidth(width, Bpp, depth),
       height: height,
@@ -104,7 +106,20 @@ Filter.prototype._reverseFilterLine = function(rawData) {
 
   var filter = rawData[0];
 
-  var xComparison = this._depth >= 8 ? ((this._depth === 16) ? this._Bpp * 2 : this._Bpp) : 1;
+  // when filtering the line we look at the pixel to the left
+  // the spec also says it is done on a byte level regardless of the number of pixels
+  // so if the depth is byte compatible (8 or 16) we subtract the bpp in order to compare back
+  // a pixel rather than just a different byte part. However if we are sub byte, we ignore.
+  var xComparison;
+  if (this._depth === 8) {
+    xComparison = this._Bpp;
+  }
+  else if (this._depth === 16) {
+    xComparison = this._Bpp * 2;
+  }
+  else {
+    xComparison = 1;
+  }
   var xBiggerThan = xComparison - 1;
 
   for (var x = 0; x < currentImage.byteWidth; x++) {
@@ -114,27 +129,29 @@ Filter.prototype._reverseFilterLine = function(rawData) {
         line[x] = rawByte;
         break;
       case 1:
-        var f1_left = x > xBiggerThan ? line[x - xComparison] : 0;
-        line[x] = rawByte + f1_left;
+        var f1Left = x > xBiggerThan ? line[x - xComparison] : 0;
+        line[x] = rawByte + f1Left;
         break;
       case 2:
-        var f2_up = this._lastLine ? this._lastLine[x] : 0;
-        line[x] = rawByte + f2_up;
+        var f2Up = this._lastLine ? this._lastLine[x] : 0;
+        line[x] = rawByte + f2Up;
         break;
       case 3:
-        var f3_up = this._lastLine ? this._lastLine[x] : 0;
-        var f3_left = x > xBiggerThan ? line[x - xComparison] : 0;
-        var f3_add = Math.floor((f3_left + f3_up) / 2);
-        line[x] = rawByte + f3_add;
+        var f3Up = this._lastLine ? this._lastLine[x] : 0;
+        var f3Left = x > xBiggerThan ? line[x - xComparison] : 0;
+        var f3Add = Math.floor((f3Left + f3Up) / 2);
+        line[x] = rawByte + f3Add;
         break;
       case 4:
-        var f4_up = this._lastLine ? this._lastLine[x] : 0;
-        var f4_left = x > xBiggerThan ? line[x - xComparison] : 0;
-        var f4_upLeft = x > xBiggerThan && this._lastLine
+        var f4Up = this._lastLine ? this._lastLine[x] : 0;
+        var f4Left = x > xBiggerThan ? line[x - xComparison] : 0;
+        var f4UpLeft = x > xBiggerThan && this._lastLine
           ? this._lastLine[x - xComparison] : 0;
-        var f4_add = PaethPredictor(f4_left, f4_up, f4_upLeft);
-        line[x] = rawByte + f4_add;
+        var f4Add = paethPredictor(f4Left, f4Up, f4UpLeft);
+        line[x] = rawByte + f4Add;
         break;
+      default:
+        throw new Error('Unrecognised filter type - ' + filter);
     }
 
     //if (x === 5) {
@@ -149,18 +166,20 @@ Filter.prototype._reverseFilterLine = function(rawData) {
     this._lastLine = null;
     this._imageIndex++;
     currentImage = this._images[this._imageIndex];
-  } else {
+  }
+  else {
     this._lastLine = line;
   }
 
   if (currentImage) {
     this.read(currentImage.byteWidth + 1, this._reverseFilterLine.bind(this));
-  } else {
+  }
+  else {
     this.complete(this._width, this._height);
   }
 };
 
-
+//TODO pull out
 Filter.prototype.filter = function(pxData) {
 
   var rawData = new Buffer(((this._width << 2) + 1) * this._height);
@@ -168,9 +187,9 @@ Filter.prototype.filter = function(pxData) {
   for (var y = 0; y < this._height; y++) {
 
     // find best filter for this line (with lowest sum of values)
-    var filterTypes = this._options.filterType,
-      min = Infinity,
-      sel = 0;
+    var filterTypes = this._options.filterType;
+    var min = Infinity;
+    var sel = 0;
 
     for (var i = 0; i < filterTypes.length; i++) {
       var sum = this._filters[filterTypes[i]](pxData, y, null);
@@ -187,15 +206,17 @@ Filter.prototype.filter = function(pxData) {
 
 Filter.prototype._filterNone = function(pxData, y, rawData) {
 
-  var pxRowLength = this._width << 2,
-    rawRowLength = pxRowLength + 1,
-    sum = 0;
+  var pxRowLength = this._width << 2;
+  var rawRowLength = pxRowLength + 1;
+  var sum = 0;
 
   if (!rawData) {
-    for (var x = 0; x < pxRowLength; x++)
+    for (var x = 0; x < pxRowLength; x++) {
       sum += Math.abs(pxData[y * pxRowLength + x]);
+    }
 
-  } else {
+  }
+  else {
     rawData[y * rawRowLength] = 0;
     pxData.copy(rawData, rawRowLength * y + 1, pxRowLength * y, pxRowLength * (y + 1));
   }
@@ -205,83 +226,103 @@ Filter.prototype._filterNone = function(pxData, y, rawData) {
 
 Filter.prototype._filterSub = function(pxData, y, rawData) {
 
-  var pxRowLength = this._width << 2,
-    rawRowLength = pxRowLength + 1,
-    sum = 0;
+  var pxRowLength = this._width << 2;
+  var rawRowLength = pxRowLength + 1;
+  var sum = 0;
 
-  if (rawData)
+  if (rawData) {
     rawData[y * rawRowLength] = 1;
+  }
 
   for (var x = 0; x < pxRowLength; x++) {
 
-    var left = x >= 4 ? pxData[y * pxRowLength + x - 4] : 0,
-      val = pxData[y * pxRowLength + x] - left;
+    var left = x >= 4 ? pxData[y * pxRowLength + x - 4] : 0;
+    var val = pxData[y * pxRowLength + x] - left;
 
-    if (!rawData) sum += Math.abs(val);
-    else rawData[y * rawRowLength + 1 + x] = val;
+    if (!rawData) {
+      sum += Math.abs(val);
+    }
+    else {
+      rawData[y * rawRowLength + 1 + x] = val;
+    }
   }
   return sum;
 };
 
 Filter.prototype._filterUp = function(pxData, y, rawData) {
 
-  var pxRowLength = this._width << 2,
-    rawRowLength = pxRowLength + 1,
-    sum = 0;
+  var pxRowLength = this._width << 2;
+  var rawRowLength = pxRowLength + 1;
+  var sum = 0;
 
-  if (rawData)
+  if (rawData) {
     rawData[y * rawRowLength] = 2;
+  }
 
   for (var x = 0; x < pxRowLength; x++) {
 
-    var up = y > 0 ? pxData[(y - 1) * pxRowLength + x] : 0,
-      val = pxData[y * pxRowLength + x] - up;
+    var up = y > 0 ? pxData[(y - 1) * pxRowLength + x] : 0;
+    var val = pxData[y * pxRowLength + x] - up;
 
-    if (!rawData) sum += Math.abs(val);
-    else rawData[y * rawRowLength + 1 + x] = val;
+    if (!rawData) {
+      sum += Math.abs(val);
+    }
+    else {
+      rawData[y * rawRowLength + 1 + x] = val;
+    }
   }
   return sum;
 };
 
 Filter.prototype._filterAvg = function(pxData, y, rawData) {
 
-  var pxRowLength = this._width << 2,
-    rawRowLength = pxRowLength + 1,
-    sum = 0;
+  var pxRowLength = this._width << 2;
+  var rawRowLength = pxRowLength + 1;
+  var sum = 0;
 
-  if (rawData)
+  if (rawData) {
     rawData[y * rawRowLength] = 3;
+  }
 
   for (var x = 0; x < pxRowLength; x++) {
 
-    var left = x >= 4 ? pxData[y * pxRowLength + x - 4] : 0,
-      up = y > 0 ? pxData[(y - 1) * pxRowLength + x] : 0,
-      val = pxData[y * pxRowLength + x] - ((left + up) >> 1);
+    var left = x >= 4 ? pxData[y * pxRowLength + x - 4] : 0;
+    var up = y > 0 ? pxData[(y - 1) * pxRowLength + x] : 0;
+    var val = pxData[y * pxRowLength + x] - ((left + up) >> 1);
 
-    if (!rawData) sum += Math.abs(val);
-    else rawData[y * rawRowLength + 1 + x] = val;
+    if (!rawData) {
+      sum += Math.abs(val);
+    }
+    else {
+      rawData[y * rawRowLength + 1 + x] = val;
+    }
   }
   return sum;
 };
 
 Filter.prototype._filterPaeth = function(pxData, y, rawData) {
 
-  var pxRowLength = this._width << 2,
-    rawRowLength = pxRowLength + 1,
-    sum = 0;
+  var pxRowLength = this._width << 2;
+  var rawRowLength = pxRowLength + 1;
+  var sum = 0;
 
-  if (rawData)
+  if (rawData) {
     rawData[y * rawRowLength] = 4;
+  }
 
   for (var x = 0; x < pxRowLength; x++) {
 
-    var left = x >= 4 ? pxData[y * pxRowLength + x - 4] : 0,
-      up = y > 0 ? pxData[(y - 1) * pxRowLength + x] : 0,
-      upLeft = x >= 4 && y > 0 ? pxData[(y - 1) * pxRowLength + x - 4] : 0,
-      val = pxData[y * pxRowLength + x] - PaethPredictor(left, up, upLeft);
+    var left = x >= 4 ? pxData[y * pxRowLength + x - 4] : 0;
+    var up = y > 0 ? pxData[(y - 1) * pxRowLength + x] : 0;
+    var upLeft = x >= 4 && y > 0 ? pxData[(y - 1) * pxRowLength + x - 4] : 0;
+    var val = pxData[y * pxRowLength + x] - paethPredictor(left, up, upLeft);
 
-    if (!rawData) sum += Math.abs(val);
-    else rawData[y * rawRowLength + 1 + x] = val;
+    if (!rawData) {
+      sum += Math.abs(val);
+    }
+    else {
+      rawData[y * rawRowLength + 1 + x] = val;
+    }
   }
   return sum;
 };
diff --git a/lib/interlace.js b/lib/interlace.js
index aa76668..cc76542 100644
--- a/lib/interlace.js
+++ b/lib/interlace.js
@@ -70,7 +70,7 @@ exports.getImagePasses = function(width, height) {
       }
     }
     if (passWidth > 0 && passHeight > 0) {
-      images.push({width: passWidth, height: passHeight, index: i});
+      images.push({ width: passWidth, height: passHeight, index: i });
     }
   }
   return images;
diff --git a/lib/packer.js b/lib/packer.js
index 85ec1ed..0bf0af9 100755
--- a/lib/packer.js
+++ b/lib/packer.js
@@ -76,13 +76,15 @@ Packer.prototype.pack = function(data, width, height) {
 
 Packer.prototype._packChunk = function(type, data) {
 
-  var len = (data ? data.length : 0),
-    buf = new Buffer(len + 12);
+  var len = (data ? data.length : 0);
+  var buf = new Buffer(len + 12);
 
   buf.writeUInt32BE(len, 0);
   buf.writeUInt32BE(type, 4);
 
-  if (data) data.copy(buf, 8);
+  if (data) {
+    data.copy(buf, 8);
+  }
 
   buf.writeInt32BE(CrcStream.crc32(buf.slice(4, buf.length - 4)), buf.length - 4);
   return buf;
diff --git a/lib/parser-async.js b/lib/parser-async.js
index f3d1d7a..61b3352 100644
--- a/lib/parser-async.js
+++ b/lib/parser-async.js
@@ -35,8 +35,8 @@ var ParserAsync = module.exports = function(options) {
   this._parser = new Parser(options, {
     read: this.read.bind(this),
     error: this._handleError.bind(this),
-    metadata: this.emit.bind(this, "metadata"),
-    gamma: this.emit.bind(this, "gamma"),
+    metadata: this.emit.bind(this, 'metadata'),
+    gamma: this.emit.bind(this, 'gamma'),
     finished: this._finished.bind(this),
     inflateData: this._inflateData.bind(this),
     createData: this._createData.bind(this)
@@ -98,31 +98,32 @@ ParserAsync.prototype._finished = function() {
 
   if (!this._inflate) {
     this.emit('error', 'No Inflate block');
-  } else {
+  }
+  else {
     // no more data to inflate
     this._inflate.end();
   }
   this.destroySoon();
 };
 
-ParserAsync.prototype._complete = function(data, width, height) {
+ParserAsync.prototype._complete = function(filteredData, width, height) {
 
   if (this.errord) {
     return;
   }
 
   try {
-    data = bitmapper.dataToBitMap(data, width, height,
+    var bitmapData = bitmapper.dataToBitMap(filteredData, width, height,
       this._bpp,
       this._depth,
       this._interlace);
 
-    data = this._parser.reverseFiltered(data, this._depth, width, height);
+    bitmapData = this._parser.reverseFiltered(bitmapData, this._depth, width, height);
   }
-  catch (e) {
-    this._handleError();
+  catch (ex) {
+    this._handleError(ex);
     return;
   }
 
-  this.emit('parsed', data);
+  this.emit('parsed', bitmapData);
 };
diff --git a/lib/parser.js b/lib/parser.js
index 726fce2..01869b2 100644
--- a/lib/parser.js
+++ b/lib/parser.js
@@ -74,7 +74,7 @@ Parser.prototype._parseSignature = function(data) {
   var signature = constants.PNG_SIGNATURE;
 
   for (var i = 0; i < signature.length; i++) {
-    if (data[i] != signature[i]) {
+    if (data[i] !== signature[i]) {
       this.error(new Error('Invalid file signature'));
       return;
     }
@@ -88,8 +88,8 @@ Parser.prototype._parseChunkBegin = function(data) {
   var length = data.readUInt32BE(0);
 
   // chunk type
-  var type = data.readUInt32BE(4),
-    name = '';
+  var type = data.readUInt32BE(4);
+  var name = '';
   for (var i = 4; i < 8; i++) {
     name += String.fromCharCode(data[i]);
   }
@@ -97,11 +97,11 @@ Parser.prototype._parseChunkBegin = function(data) {
   //console.log('chunk ', name, length);
 
   // chunk flags
-  var ancillary = !!(data[4] & 0x20); // or critical
-//    priv = !!(data[5] & 0x20), // or public
-//    safeToCopy = !!(data[7] & 0x20); // or unsafe
+  var ancillary = Boolean(data[4] & 0x20); // or critical
+//    priv = Boolean(data[5] & 0x20), // or public
+//    safeToCopy = Boolean(data[7] & 0x20); // or unsafe
 
-  if (!this._hasIHDR && type != constants.TYPE_IHDR) {
+  if (!this._hasIHDR && type !== constants.TYPE_IHDR) {
     this.error(new Error('Expected IHDR on beggining'));
     return;
   }
@@ -131,12 +131,12 @@ Parser.prototype._handleChunkEnd = function() {
 
 Parser.prototype._parseChunkEnd = function(data) {
 
-  var fileCrc = data.readInt32BE(0),
-    calcCrc = this._crc.crc32();
+  var fileCrc = data.readInt32BE(0);
+  var calcCrc = this._crc.crc32();
 
   // check CRC
-  if (this._options.checkCRC && calcCrc != fileCrc) {
-    this.error(new Error('Crc error - ' + fileCrc + " - " + calcCrc));
+  if (this._options.checkCRC && calcCrc !== fileCrc) {
+    this.error(new Error('Crc error - ' + fileCrc + ' - ' + calcCrc));
     return;
   }
 
@@ -152,13 +152,13 @@ Parser.prototype._parseIHDR = function(data) {
 
   this._crc.write(data);
 
-  var width = data.readUInt32BE(0),
-    height = data.readUInt32BE(4),
-    depth = data[8],
-    colorType = data[9], // bits: 1 palette, 2 color, 4 alpha
-    compr = data[10],
-    filter = data[11],
-    interlace = data[12];
+  var width = data.readUInt32BE(0);
+  var height = data.readUInt32BE(4);
+  var depth = data[8];
+  var colorType = data[9]; // bits: 1 palette, 2 color, 4 alpha
+  var compr = data[10];
+  var filter = data[11];
+  var interlace = data[12];
 
   // console.log('    width', width, 'height', height,
   //     'depth', depth, 'colorType', colorType,
@@ -173,15 +173,15 @@ Parser.prototype._parseIHDR = function(data) {
     this.error(new Error('Unsupported color type'));
     return;
   }
-  if (compr != 0) {
+  if (compr !== 0) {
     this.error(new Error('Unsupported compression method'));
     return;
   }
-  if (filter != 0) {
+  if (filter !== 0) {
     this.error(new Error('Unsupported filter method'));
     return;
   }
-  if (interlace != 0 && interlace !== 1) {
+  if (interlace !== 0 && interlace !== 1) {
     this.error(new Error('Unsupported interlace method'));
     return;
   }
@@ -197,10 +197,10 @@ Parser.prototype._parseIHDR = function(data) {
     width: width,
     height: height,
     depth: depth,
-    interlace: interlace,
-    palette: !!(colorType & constants.COLOR_PALETTE),
-    color: !!(colorType & constants.COLOR_COLOR),
-    alpha: !!(colorType & constants.COLOR_ALPHA)
+    interlace: Boolean(interlace),
+    palette: Boolean(colorType & constants.COLOR_PALETTE),
+    color: Boolean(colorType & constants.COLOR_COLOR),
+    alpha: Boolean(colorType & constants.COLOR_ALPHA)
   });
 
   this._handleChunkEnd();
@@ -237,8 +237,8 @@ Parser.prototype._parseTRNS = function(data) {
   this._crc.write(data);
 
   // palette
-  if (this._colorType == 3) {
-    if (this._palette.length == 0) {
+  if (this._colorType === 3) {
+    if (this._palette.length === 0) {
       this.error(new Error('Transparency chunk must be after palette'));
       return;
     }
@@ -282,16 +282,19 @@ Parser.prototype._parseIDAT = function(length, data) {
 
   this._crc.write(data);
 
-  if (this._colorType == 3 && this._palette.length == 0)
+  if (this._colorType === 3 && this._palette.length === 0) {
     throw new Error('Expected palette not found');
+  }
 
   this.inflateData(data);
-  length -= data.length;
+  var leftOverLength = length - data.length;
 
-  if (length > 0)
-    this._handleIDAT(length);
-  else
+  if (leftOverLength > 0) {
+    this._handleIDAT(leftOverLength);
+  }
+  else {
     this._handleChunkEnd();
+  }
 };
 
 
@@ -315,7 +318,7 @@ Parser.prototype.reverseFiltered = function(indata, depth, width, height) {
   var pxLineLength = width << 2;
   var x, y, i, pxPos, pxRowPos;
 
-  if (this._colorType == 3) { // paletted
+  if (this._colorType === 3) { // paletted
     //TODO abstract loop?
     // use values from palette
     for (y = 0; y < height; y++) {
@@ -326,14 +329,16 @@ Parser.prototype.reverseFiltered = function(indata, depth, width, height) {
         var color = this._palette[indata[pxPos]];
 
         if (!color) {
-          throw new Error("index " + indata[pxPos] + " not in palette");
+          throw new Error('index ' + indata[pxPos] + ' not in palette');
         }
 
-        for (i = 0; i < 4; i++)
+        for (i = 0; i < 4; i++) {
           indata[pxPos + i] = color[i];
+        }
       }
     }
-  } else {
+  }
+  else {
     if (this._transColor) {
       for (y = 0; y < height; y++) {
         pxRowPos = y * pxLineLength;
@@ -346,7 +351,8 @@ Parser.prototype.reverseFiltered = function(indata, depth, width, height) {
             if (this._transColor[0] === indata[pxPos]) {
               makeTrans = true;
             }
-          } else if (this._transColor[0] === indata[pxPos] && this._transColor[1] === indata[pxPos + 1] && this._transColor[2] === indata[pxPos + 2]) {
+          }
+          else if (this._transColor[0] === indata[pxPos] && this._transColor[1] === indata[pxPos + 1] && this._transColor[2] === indata[pxPos + 2]) {
             makeTrans = true;
           }
           if (makeTrans) {
@@ -370,8 +376,9 @@ Parser.prototype.reverseFiltered = function(indata, depth, width, height) {
 
         for (x = 0; x < width; x++) {
           pxPos = pxRowPos + (x << 2);
-          for (i = 0; i < 4; i++)
+          for (i = 0; i < 4; i++) {
             outdata[pxPos + i] = Math.floor((indata[pxPos + i] * maxOutSample) / maxInSample + 0.5);
+          }
         }
       }
     }
diff --git a/lib/sync-reader.js b/lib/sync-reader.js
index 0718f36..3ca1ae3 100644
--- a/lib/sync-reader.js
+++ b/lib/sync-reader.js
@@ -53,7 +53,8 @@ SyncReader.prototype.process = function() {
 
       read.func.call(this, buf.slice(0, read.length));
 
-    } else {
+    }
+    else {
       break;
     }