refactor code

lib/hdprivatekey.js

@@ -365,6 +365,15 @@ HDPrivateKey.fromSeed = function(hexa, network) {
   });
 };
 
+
+
+HDPrivateKey.prototype._calcHDPublicKey = function() {
+  if (!this._hdPublicKey) {
+    var HDPublicKey = require('./hdpublickey');
+    this._hdPublicKey = new HDPublicKey(this);
+  }
+};
+
 /**
  * Receives a object with buffers in all the properties and populates the
  * internal structure
@@ -424,14 +433,12 @@ HDPrivateKey.prototype._buildFromBuffers = function(arg) {
   });
 
   this._hdPublicKey = null;
+
   Object.defineProperty(this, 'hdPublicKey', {
     configurable: false,
     enumerable: true,
     get: function() {
-      if (!this._hdPublicKey) {
+      this._calcHDPublicKey();
-        var HDPublicKey = require('./hdpublickey');
-        this._hdPublicKey = new HDPublicKey(this);
-      }
       return this._hdPublicKey;
     }
   });
@@ -439,10 +446,7 @@ HDPrivateKey.prototype._buildFromBuffers = function(arg) {
     configurable: false,
     enumerable: true,
     get: function() {
-      if (!this._hdPublicKey) {
+      this._calcHDPublicKey();
-        var HDPublicKey = require('./hdpublickey');
-        this._hdPublicKey = new HDPublicKey(this);
-      }
       return this._hdPublicKey.xpubkey;
     }
   });