Script: adds Script.EMPTY constant

src/script.js

@@ -414,4 +414,7 @@ Script.prototype.without = function(needle) {
   }))
 }
 
+// Constants
+Script.EMPTY = new Script()
+
 module.exports = Script

src/transaction.js

@@ -76,7 +76,7 @@ Transaction.prototype.addInput = function (tx, outIndex) {
       hash: hash,
       index: outIndex
     },
-    script: new Script()
+    script: Script.EMPTY
   }))
 }
 
@@ -206,7 +206,7 @@ Transaction.prototype.hashForSignature = function(scriptPubKey, inIndex, hashTyp
 
   // Blank out other inputs' signatures
   txTmp.ins.forEach(function(txin) {
-    txin.script = new Script()
+    txin.script = Script.EMPTY
   })
   txTmp.ins[inIndex].script = hashScript
 

test/transaction.js

@@ -140,7 +140,7 @@ describe('Transaction', function() {
         assert.equal(input.outpoint.index, 0)
         assert.equal(input.outpoint.hash, "0cb859105100ebc3344f749c835c7af7d7103ec0d8cbc3d8ccbd5d28c3c36b57")
 
-        assert.deepEqual(input.script.buffer, [])
+        assert.equal(input.script, Script.EMPTY)
       }
     })