Refactor Move to adhere to OCP and LSP

OCP is Open/Closed Principle
LSP is Liskov substitution principle

Author: marcinbunsch

app/dot.coffee

@@ -1,6 +1,6 @@
 Colors = require('colors')
 Entity = require('entity')
-Move = require('move')
+Move = require('move_with_squares')
 
 class Dot extends Entity
 

app/move.coffee

@@ -12,25 +12,11 @@ class Move
 
   complete: =>
     Crafty.removeEvent this, Crafty.stage.elem, "mouseup", this.complete
-    if this.squarePresent()
-      this.addAllSameColoredDots()
     this.destroyDots()
     this.destroyAllLines()
     this.updateGameState()
     this.dispose()
 
-  squarePresent: =>
-    groupedDots = this.getGroupedDots()
-    for id, dots of groupedDots
-      return true if dots.length > 1
-    return false
-
-  addAllSameColoredDots: =>
-    uniqueDots = this.getUniqueDots()
-    @game.dots.forEach (dot) =>
-      if dot.color == @color and !uniqueDots[dot.id]
-        @dots.push(dot)
-
   updateGameState: =>
     if @dots.length > 1
       dotCount = this.getUniqueDotCount()
@@ -174,3 +160,4 @@ class Move
     @dots.push(dot)
 
 module.exports = Move
+

app/move_with_squares.coffee

@@ -0,0 +1,22 @@
+Move = require('move')
+
+class MoveWithSquares extends Move
+
+  complete: =>
+    if this.squarePresent()
+      this.addAllSameColoredDots()
+    super()
+
+  squarePresent: =>
+    groupedDots = this.getGroupedDots()
+    for id, dots of groupedDots
+      return true if dots.length > 1
+    return false
+
+  addAllSameColoredDots: =>
+    uniqueDots = this.getUniqueDots()
+    @game.dots.forEach (dot) =>
+      if dot.color == @color and !uniqueDots[dot.id]
+        @dots.push(dot)
+
+module.exports = MoveWithSquares