diff --git a/src/BrailleBuffer.coffee b/src/BrailleBuffer.coffee
deleted file mode 100644
index 643cb0e..0000000
--- a/src/BrailleBuffer.coffee
+++ /dev/null
@@ -1,156 +0,0 @@
-###
-  termap - Terminal Map Viewer
-  by Michael Strassburger <codepoet@cpan.org>
-
-  Simple pixel to barille character mapper
-
-  Implementation inspired by node-drawille (https://github.com/madbence/node-drawille)
-  * added color support
-  * added text label support
-  * general optimizations
-
-  Will either be merged into node-drawille or become an own module at some point
-###
-stringWidth = require 'string-width'
-config = require './config'
-utils = require './utils'
-
-module.exports = class BrailleBuffer
-  brailleMap: [[0x1, 0x8],[0x2, 0x10],[0x4, 0x20],[0x40, 0x80]]
-  asciiMap:
-    # "▬": [2+32, 4+64]
-    # "¯": [1+16]
-    "▀": [1+2+16+32]
-    "▄": [4+8+64+128]
-    "■": [2+4+32+64]
-    "▌": [1+2+4+8]
-    "▐": [16+32+64+128]
-    # "▓": [1+4+32+128, 2+8+16+64]
-    "█": [255]
-
-  pixelBuffer: null
-  charBuffer: null
-  foregroundBuffer: null
-  backgroundBuffer: null
-
-  asciiToBraille: []
-
-  globalBackground: null
-
-  termReset: "\x1B[39;49m"
-
-  constructor: (@width, @height) ->
-    size = @width*@height/8
-    @pixelBuffer = new Buffer size
-    @foregroundBuffer = new Buffer size
-    @backgroundBuffer = new Buffer size
-
-    @_mapBraille()
-    @clear()
-
-  clear: ->
-    @pixelBuffer.fill 0
-    @charBuffer = []
-    @foregroundBuffer.fill 0
-    @backgroundBuffer.fill 0
-
-  setGlobalBackground: (@globalBackground) ->
-
-  setBackground: (x, y, color) ->
-    return unless 0 <= x < @width and 0 <= y < @height
-    idx = @_project x, y
-    @backgroundBuffer[idx] = color
-
-  setPixel: (x, y, color) ->
-    @_locate x, y, (idx, mask) =>
-      @pixelBuffer[idx] |= mask
-      @foregroundBuffer[idx] = color
-
-  unsetPixel: (x, y) ->
-    @_locate x, y, (idx, mask) =>
-      @pixelBuffer[idx] &= ~mask
-
-  _project: (x, y) ->
-    (x>>1) + (@width>>1)*(y>>2)
-
-  _locate: (x, y, cb) ->
-    return unless 0 <= x < @width and 0 <= y < @height
-    idx = @_project x, y
-    mask = @brailleMap[y&3][x&1]
-    cb idx, mask
-
-  _mapBraille: ->
-    @asciiToBraille = [" "]
-
-    masks = []
-    for char, bits of @asciiMap
-      continue unless bits instanceof Array
-      masks.push mask: mask, char: char for mask in bits
-
-    for i in [1..255]
-      braille = (i&7) + ((i&56)<<1) + ((i&64)>>3) + (i&128)
-
-      @asciiToBraille[i] = masks.reduce(((best, mask) ->
-        covered = utils.population(mask.mask&braille)
-        if not best or best.covered < covered
-          char: mask.char, covered: covered
-        else
-          best
-      ), undefined).char
-
-  _termColor: (foreground, background) ->
-    background = background or @globalBackground
-    if foreground and background
-      "\x1B[38;5;#{foreground};48;5;#{background}m"
-    else if foreground
-      "\x1B[49;38;5;#{foreground}m"
-    else if background
-      "\x1B[39;48;5;#{background}m"
-    else
-      @termReset
-
-  frame: ->
-    output = []
-    currentColor = null
-    skip = 0
-
-    for y in [0...@height/4]
-      skip = 0
-
-      for x in [0...@width/2]
-        idx = y*@width/2 + x
-
-        if idx and not x
-          output.push config.delimeter
-
-        if currentColor isnt colorCode = @_termColor @foregroundBuffer[idx], @backgroundBuffer[idx]
-          output.push currentColor = colorCode
-
-        output.push if char = @charBuffer[idx]
-          skip += stringWidth(char)-1
-          if skip+x >= @width/2
-            ''
-          else
-            char
-        else
-          if not skip
-            if config.useBraille
-              String.fromCharCode 0x2800+@pixelBuffer[idx]
-            else
-              @asciiToBraille[@pixelBuffer[idx]]
-          else
-            skip--
-            ''
-
-    output.push @termReset+config.delimeter
-    output.join ''
-
-  setChar: (char, x, y, color) ->
-    return unless 0 <= x < @width and 0 <= y < @height
-    idx = @_project x, y
-    @charBuffer[idx] = char
-    @foregroundBuffer[idx] = color
-
-  writeText: (text, x, y, color, center = true) ->
-    x -= text.length/2+1 if center
-    @setChar text.charAt(i), x+i*2, y, color for i in [0...text.length]
diff --git a/src/BrailleBuffer.js b/src/BrailleBuffer.js
new file mode 100644
index 0000000..6266030
--- /dev/null
+++ b/src/BrailleBuffer.js
@@ -0,0 +1,211 @@
+/*
+  termap - Terminal Map Viewer
+  by Michael Strassburger <codepoet@cpan.org>
+
+  Simple pixel to barille character mapper
+
+  Implementation inspired by node-drawille (https://github.com/madbence/node-drawille)
+  * added color support
+  * added text label support
+  * general optimizations
+
+  Will either be merged into node-drawille or become an own module at some point
+*/
+'use strict';
+const stringWidth = require('string-width');
+const config = require('./config');
+const utils = require('./utils');
+
+const asciiMap = {
+  // '▬': [2+32, 4+64],
+  // '¯': [1+16],
+  '▀': [1+2+16+32],
+  '▄': [4+8+64+128],
+  '■': [2+4+32+64],
+  '▌': [1+2+4+8],
+  '▐': [16+32+64+128],
+  // '▓': [1+4+32+128, 2+8+16+64],
+  '█': [255],
+};
+const termReset = '\x1B[39;49m';
+
+class BrailleBuffer {
+  constructor(width, height) {
+    this.brailleMap = [[0x1, 0x8],[0x2, 0x10],[0x4, 0x20],[0x40, 0x80]]
+
+    this.pixelBuffer = null;
+    this.charBuffer = null;
+    this.foregroundBuffer = null;
+    this.backgroundBuffer = null;
+
+    this.asciiToBraille = [];
+
+    this.globalBackground = null;
+
+    this.width = width;
+    this.height = height;
+
+    const size = width*height/8;
+    this.pixelBuffer = new Buffer(size);
+    this.foregroundBuffer = new Buffer(size);
+    this.backgroundBuffer = new Buffer(size);
+
+    this._mapBraille();
+    this.clear();
+  }
+
+  clear() {
+    this.pixelBuffer.fill(0);
+    this.charBuffer = [];
+    this.foregroundBuffer.fill(0);
+    this.backgroundBuffer.fill(0);
+  }
+
+  setGlobalBackground(background) {
+    this.globalBackground = background;
+  }
+
+  setBackground(x, y, color) {
+    if (0 <= x && x < this.width && 0 <= y && y < this.height) {
+      idx = this._project(x, y);
+      this.backgroundBuffer[idx] = color;
+    }
+  }
+
+  setPixel(x, y, color) {
+    this._locate(x, y, (idx, mask) => {
+      this.pixelBuffer[idx] |= mask;
+      this.foregroundBuffer[idx] = color;
+    });
+  }
+
+  unsetPixel(x, y) {
+    this._locate(x, y, (idx, mask) => {
+      this.pixelBuffer[idx] &= ~mask;
+    });
+  }
+
+  _project(x, y) {
+    return (x>>1) + (this.width>>1)*(y>>2);
+  }
+
+  _locate(x, y, cb) {
+    if (!((0 <= x && x < this.width) && (0 <= y && y < this.height))) {
+      return;
+    }
+    const idx = this._project(x, y);
+    const mask = this.brailleMap[y & 3][x & 1];
+    return cb(idx, mask);
+  }
+
+  _mapBraille() {
+    this.asciiToBraille = [' '];
+
+    const masks = [];
+    for (const char in asciiMap) {
+      const bits = asciiMap[char];
+      if (!(bits instanceof Array)) continue;
+      for (const mask of bits) {
+        masks.push({
+          mask: mask,
+          char: char,
+        });
+      }
+    }
+
+    //TODO Optimize this part
+    var i, k;
+    const results = [];
+    for (i = k = 1; k <= 255; i = ++k) {
+      const braille = (i & 7) + ((i & 56) << 1) + ((i & 64) >> 3) + (i & 128);
+      results.push(this.asciiToBraille[i] = masks.reduce((function(best, mask) {
+        const covered = utils.population(mask.mask & braille);
+        if (!best || best.covered < covered) {
+          return {
+            char: mask.char,
+            covered: covered,
+          };
+        } else {
+          return best;
+        }
+      }), void 0).char);
+    }
+    return results;
+  }
+
+  _termColor(foreground, background) {
+    background |= this.globalBackground;
+    if (foreground && background) {
+      return `\x1B[38;5;${foreground};48;5;${background}m`;
+    } else if (foreground) {
+      return `\x1B[49;38;5;${foreground}m`;
+    } else if (background) {
+      return `\x1B[39;48;5;${background}m`;
+    } else {
+      return termReset;
+    }
+  }
+
+  frame() {
+    const output = [];
+    let currentColor = null;
+    let skip = 0;
+
+    for (let y = 0; y < this.height/4; y++) {
+      skip = 0;
+
+      for (let x = 0; x < this.width/2; x++) {
+        const idx = y*this.width/2 + x;
+
+        if (idx && !x) {
+          output.push(config.delimeter);
+        }
+
+        const colorCode = this._termColor(this.foregroundBuffer[idx], this.backgroundBuffer[idx]);
+        if (currentColor !== colorCode) {
+          output.push(currentColor = colorCode);
+        }
+
+        const char = this.charBuffer[idx];
+        if (char) {
+          skip += stringWidth(char)-1;
+          if (skip+x < this.width/2) {
+            output.push(char);
+          }
+        } else {
+          if (!skip) {
+            if (config.useBraille) {
+              output.push(String.fromCharCode(0x2800+this.pixelBuffer[idx]));
+            } else {
+              output.push(this.asciiToBraille[this.pixelBuffer[idx]]);
+            }
+          } else {
+            skip--;
+          }
+        }
+      }
+    }
+
+    output.push(termReset+config.delimeter);
+    return output.join('');
+  }
+
+  setChar(char, x, y, color) {
+    if (0 <= x && x < this.width && 0 <= y && y < this.height) {
+      const idx = this._project(x, y);
+      this.charBuffer[idx] = char;
+      this.foregroundBuffer[idx] = color;
+    }
+  }
+
+  writeText(text, x, y, color, center = true) {
+    if (center) {
+      x -= text.length/2+1;
+    }
+    for (let i = 0; i < text.length; i++) {
+      this.setChar(text.charAt(i), x+i*2, y, color);
+    }
+  }
+}
+
+module.exports = BrailleBuffer;