Expose estimateFee method.

integration/regtest.js

@@ -232,6 +232,13 @@ describe('Daemon Binding Functionality', function() {
 
   });
 
+  describe('fee estimation', function() {
+    it('will estimate fees', function() {
+      var fees = bitcoind.estimateFee();
+      fees.should.equal(-1);
+    });
+  });
+
   describe('tip updates', function() {
     it('will get an event when the tip is new', function(done) {
       this.timeout(4000);

lib/daemon.js

@@ -296,6 +296,10 @@ Daemon.prototype.getBlockIndex = function(blockHash) {
   return bitcoindjs.getBlockIndex(blockHash);
 };
 
+Daemon.prototype.estimateFee = function(blocks) {
+  return bitcoindjs.estimateFee(blocks);
+};
+
 Daemon.prototype.sendTransaction = function(transaction, allowAbsurdFees) {
   return bitcoindjs.sendTransaction(transaction, allowAbsurdFees);
 };

src/bitcoindjs.cc

@@ -1121,6 +1121,33 @@ NAN_METHOD(GetInfo) {
   NanReturnValue(obj);
 }
 
+/**
+ * Estimate Fee
+ * @blocks {number} - The number of blocks until confirmed
+ */
+
+NAN_METHOD(EstimateFee) {
+  Isolate* isolate = Isolate::GetCurrent();
+  HandleScope scope(isolate);
+
+  int nBlocks = args[0]->NumberValue();
+  if (nBlocks < 1) {
+    nBlocks = 1;
+  }
+
+  CFeeRate feeRate = mempool.estimateFee(nBlocks);
+
+  if (feeRate == CFeeRate(0)) {
+    NanReturnValue(NanNew<Number>(-1.0));
+    return;
+  }
+
+  CAmount nFee = feeRate.GetFeePerK();
+
+  NanReturnValue(NanNew<Number>(nFee));
+
+}
+
 /**
  * Send Transaction
  * bitcoindjs.sendTransaction()
@@ -1319,6 +1346,8 @@ init(Handle<Object> target) {
   NODE_SET_METHOD(target, "addMempoolUncheckedTransaction", AddMempoolUncheckedTransaction);
   NODE_SET_METHOD(target, "verifyScript", VerifyScript);
   NODE_SET_METHOD(target, "sendTransaction", SendTransaction);
+  NODE_SET_METHOD(target, "estimateFee", EstimateFee);
+
 }
 
 NODE_MODULE(bitcoindjs, init)

src/bitcoindjs.h

@@ -29,3 +29,4 @@ NAN_METHOD(GetMempoolOutputs);
 NAN_METHOD(AddMempoolUncheckedTransaction);
 NAN_METHOD(VerifyScript);
 NAN_METHOD(SendTransaction);
+NAN_METHOD(EstimateFee);