Refactored transaction.getSerializationError to be more concise.

- _hasMoreOutputThanInput() and _isInvalidSatoshis() merged with getSerializationError()
- _isFeeDifferent(), _isFeeTooLarge() and _isFeeTooSmall merged with _hasFeeError()

lib/transaction/transaction.js

@@ -191,58 +191,54 @@ Transaction.prototype.invalidSatoshis = function() {
 Transaction.prototype.getSerializationError = function(opts) {
   opts = opts || {};
 
-  var unspent = this._getUnspentValue();
-  return this._isInvalidSatoshis() ||
-      this._hasMoreOutputThanInput(opts, unspent) ||
-      this._hasFeeError(opts, unspent) ||
-      this._hasDustOutputs(opts) ||
-      this._isMissingSignatures(opts);
-};
-
-Transaction.prototype._isInvalidSatoshis = function() {
   if (this.invalidSatoshis()) {
     return new errors.Transaction.InvalidSatoshis();
   }
-};
 
-Transaction.prototype._hasFeeError = function(opts, unspent) {
+  var unspent = this._getUnspentValue();
+  var unspentError;
   if (unspent < 0) {
-    // The concept of a fee is meaningless when the unspent output value is negative.
-    return;
+    if (!opts.disableMoreOutputThanInput) {
+      unspentError = new errors.Transaction.InvalidOutputAmountSum();
+    }
+  } else {
+    unspentError = this._hasFeeError(opts, unspent);
   }
-  return this._isFeeDifferent(unspent) ||
-      this._isFeeTooLarge(opts, unspent) ||
-      this._isFeeTooSmall(opts, unspent);
+
+  return  unspentError ||
+    this._hasDustOutputs(opts) ||
+    this._isMissingSignatures(opts);
 };
 
-Transaction.prototype._isFeeDifferent = function(unspent) {
+Transaction.prototype._hasFeeError = function(opts, unspent) {
+
   if (!_.isUndefined(this._fee) && this._fee !== unspent) {
     return new errors.Transaction.FeeError.Different(
       'Unspent value is ' + unspent + ' but specified fee is ' + this._fee
     );
   }
-};
 
-Transaction.prototype._isFeeTooLarge = function(opts, fee) {
-  if (opts.disableLargeFees) {
-    return;
-  }
-  var maximumFee = Math.floor(Transaction.FEE_SECURITY_MARGIN * this._estimateFee());
-  if (fee > maximumFee) {
-    if (this._missingChange()) {
-      return new errors.Transaction.ChangeAddressMissing('Fee is too large and no change address was provided');
+  if (!opts.disableLargeFees) {
+    var maximumFee = Math.floor(Transaction.FEE_SECURITY_MARGIN * this._estimateFee());
+    if (unspent > maximumFee) {
+      if (this._missingChange()) {
+        return new errors.Transaction.ChangeAddressMissing(
+          'Fee is too large and no change address was provided'
+        );
+      }
+      return new errors.Transaction.FeeError.TooLarge(
+        'expected less than ' + maximumFee + ' but got ' + unspent
+      );
     }
-    return new errors.Transaction.FeeError.TooLarge('expected less than ' + maximumFee + ' but got ' + fee);
   }
-};
 
-Transaction.prototype._isFeeTooSmall = function(opts, fee) {
-  if (opts.disableSmallFees) {
-    return;
-  }
-  var minimumFee = Math.ceil(this._estimateFee() / Transaction.FEE_SECURITY_MARGIN);
-  if (fee < minimumFee) {
-    return new errors.Transaction.FeeError.TooSmall('expected more than ' + minimumFee + ' but got ' + fee);
+  if (!opts.disableSmallFees) {
+    var minimumFee = Math.ceil(this._estimateFee() / Transaction.FEE_SECURITY_MARGIN);
+    if (unspent < minimumFee) {
+      return new errors.Transaction.FeeError.TooSmall(
+        'expected more than ' + minimumFee + ' but got ' + unspent
+      );
+    }
   }
 };
 
@@ -272,15 +268,6 @@ Transaction.prototype._isMissingSignatures = function(opts) {
   }
 };
 
-Transaction.prototype._hasMoreOutputThanInput = function(opts, unspent) {
-  if (opts.disableMoreOutputThanInput) {
-    return;
-  }
-  if (unspent < 0) {
-    return new errors.Transaction.InvalidOutputAmountSum();
-  }
-};
-
 Transaction.prototype.inspect = function() {
   return '<Transaction: ' + this.uncheckedSerialize() + '>';
 };