From c07d5096232be393f62ea4b0e170116ee60049a4 Mon Sep 17 00:00:00 2001
From: "Ryan X. Charles" <ryanxcharles@gmail.com>
Date: Tue, 23 Sep 2014 22:01:30 -0700
Subject: [PATCH] initialize transaction

In order to add convenience methods to a transaction, such as pushing new
inputs and outputs, we need to first have the notion of an initialized
transaction, which is actually not blank. An initialized transaction just has
default values for everything, such as no inputs and no outputs, and default
version and nlocktime.
---
 lib/transaction.js  | 15 +++++++++++++++
 test/transaction.js | 24 ++++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/lib/transaction.js b/lib/transaction.js
index aad3f45..4deb23b 100644
--- a/lib/transaction.js
+++ b/lib/transaction.js
@@ -9,6 +9,7 @@ var Transaction = function Transaction(version, txinsvi, txins, txoutsvi, txouts
   if (!(this instanceof Transaction))
     return new Transaction(version, txinsvi, txins, txoutsvi, txouts, nlocktime);
   if (typeof version === 'number') {
+    this.initialize();
     this.set({
       version: version,
       txinsvi: txinsvi,
@@ -18,14 +19,28 @@ var Transaction = function Transaction(version, txinsvi, txins, txoutsvi, txouts
       nlocktime: nlocktime
     });
   } else if (Buffer.isBuffer(version)) {
+    //not necessary to initialize, since everything should be overwritten
     var txbuf = version;
     this.fromBuffer(txbuf);
   } else if (version) {
+    this.initialize();
     var obj = version;
     this.set(obj);
+  } else {
+    this.initialize();
   }
 };
 
+Transaction.prototype.initialize = function() {
+  this.version = 1;
+  this.txinsvi = Varint(0);
+  this.txins = [];
+  this.txoutsvi = Varint(0);
+  this.txouts = [];
+  this.nlocktime = 0xffffffff;
+  return this;
+};
+
 Transaction.prototype.set = function(obj) {
   this.version = typeof obj.version !== 'undefined' ? obj.version : this.version;
   this.txinsvi = obj.txinsvi || this.txinsvi;
diff --git a/test/transaction.js b/test/transaction.js
index 180f10a..9083b56 100644
--- a/test/transaction.js
+++ b/test/transaction.js
@@ -30,7 +30,31 @@ describe('Transaction', function() {
     should.exist(tx);
     tx = Transaction();
     should.exist(tx);
+
     Transaction(txbuf).toBuffer().toString('hex').should.equal(txhex);
+    
+    //should set known defaults
+    tx.version.should.equal(1);
+    tx.txinsvi.toNumber().should.equal(0);
+    tx.txins.length.should.equal(0);
+    tx.txoutsvi.toNumber().should.equal(0);
+    tx.txouts.length.should.equal(0);
+    tx.nlocktime.should.equal(0xffffffff);
+  });
+
+  describe('#initialize', function() {
+    
+    it('should set these known defaults', function() {
+      var tx = new Transaction();
+      tx.initialize();
+      tx.version.should.equal(1);
+      tx.txinsvi.toNumber().should.equal(0);
+      tx.txins.length.should.equal(0);
+      tx.txoutsvi.toNumber().should.equal(0);
+      tx.txouts.length.should.equal(0);
+      tx.nlocktime.should.equal(0xffffffff);
+    });
+
   });
 
   describe('#set', function() {