diff --git a/lib/Format.coffee b/lib/Format.coffee
index fe16fad..81fa373 100644
--- a/lib/Format.coffee
+++ b/lib/Format.coffee
@@ -1,69 +1,74 @@
 'use strict'
 
+slice = require 'sliced'
 chalk = require 'chalk'
 
-REGEX =
-  escape: /%{2,2}/g
-  type: /(%?)(%([jds]))/g
+ESCAPE_REGEX = /%{2,2}/g
+TYPE_REGEX = /(%?)(%([jds]))/g
 
-hasWhiteSpace = (s) ->
-  s.indexOf(' ') isnt -1
+isString = (obj) -> typeof obj is 'string'
+isSymbol = (obj) -> typeof obj is 'symbol'
+isObject = (obj) -> typeof obj is 'object'
+isFalsy = (value) -> [null, undefined, false].indexOf(value) isnt -1
+isArray = (arr) -> Array.isArray(arr)
+colorize = (value, color) -> chalk[color](value)
+hasWhiteSpace = (s) -> s.indexOf(' ') isnt -1
 
 serialize = (color, obj, key) ->
   # symbols cannot be directly casted to strings
-  if typeof key is 'symbol'
-    key = key.toString()
-  if typeof obj is 'symbol'
-    obj = obj.toString()
-  if obj is null
-    obj = 'null'
-  else if obj is undefined
-    obj = 'undefined'
-  else if obj is false
-    obj = 'false'
-  if typeof obj isnt 'object'
-    obj = '\'' + obj + '\'' if key and typeof obj is 'string' and hasWhiteSpace(obj)
-    return if key then key + '=' + obj else obj
+  key = key.toString() if isSymbol key
+  obj = obj.toString() if isSymbol obj
+  obj = JSON.stringify obj if isFalsy obj
+
+  if !isObject obj
+    obj = "'#{obj}'" if key and isString obj and hasWhiteSpace obj
+    return if key then "#{key}=#{obj}" else obj
+
   if obj instanceof Buffer
-    return if key then key + '=' + obj.toString('base64') else obj.toString('base64')
-  if obj instanceof Error
-    return obj.message or obj
+    obj = obj.toString 'base64'
+    return if key then "#{key}=#{obj}" else obj
+
+  return obj.message or obj if obj instanceof Error
+
   msg = ''
   keys = Object.keys(obj)
   length = keys.length
   i = 0
   while i < length
-    if Array.isArray(obj[keys[i]])
-      msg += keys[i] + '=['
+    key = keys[i]
+    value = obj[key]
+
+    if isArray(value)
+      msg += key + '=['
       j = 0
-      l = obj[keys[i]].length
+      l = value.length
       while j < l
-        msg += serialize(color, obj[keys[i]][j])
+        msg += serialize(color, value[j])
         if j < l - 1
           msg += ' '
         j++
       msg += ']'
-    else if obj[keys[i]] instanceof Date
-      msg += keys[i] + '=' + obj[keys[i]]
+    else if value instanceof Date
+      msg += key + '=' + value
     else
-      msg += serialize(color, obj[keys[i]], chalk[color](keys[i]))
+      msg += serialize(color, value, colorize(key, color))
     if i < length - 1
       msg += ' '
     i++
   msg
 
 format = (fmt) ->
-  args = Array::slice.call(arguments, 1)
+  args = slice arguments, 1
   color = args.pop()
 
   if args.length
-    fmt = fmt.replace(REGEX.type, (match, escaped, ptn, flag) ->
+    fmt = fmt.replace(TYPE_REGEX, (match, escaped, ptn, flag) ->
       arg = args.shift()
       switch flag
         when 's'
-          arg = '' + arg
+          arg = colorize(String(arg), color)
         when 'd'
-          arg = Number(arg)
+          arg = colorize(Number(arg), color)
         when 'j'
           arg = serialize color, arg
       return arg if !escaped
@@ -72,7 +77,7 @@ format = (fmt) ->
     )
 
   fmt += ' ' + serialize color, arg for arg in args if args.length
-  fmt = fmt.replace(REGEX.escape, '%') if fmt.replace?
+  fmt = fmt.replace(ESCAPE_REGEX, '%') if fmt.replace?
   serialize color, fmt
 
 module.exports = format
diff --git a/package.json b/package.json
index 543a94a..36b1a30 100644
--- a/package.json
+++ b/package.json
@@ -27,7 +27,8 @@
   "dependencies": {
     "chalk": "~1.1.1",
     "coffee-script": "~1.12.4",
-    "pretty-ms": "~2.1.0"
+    "pretty-ms": "~2.1.0",
+    "sliced": "~1.0.1"
   },
   "devDependencies": {
     "acho-skin-cli": "latest",