node: scan method.

lib/node/fullnode.js

@@ -294,7 +294,17 @@ Fullnode.prototype.rescan = function rescan() {
   // Always rescan to make sure we didn't
   // miss anything: there is no atomicity
   // between the chaindb and walletdb.
-  return this.walletdb.rescan(this.chain.db);
+  return this.scan();
+};
+
+/**
+ * Rescan for any missed transactions.
+ * @param {Number} height
+ * @returns {Promise}
+ */
+
+Fullnode.prototype.scan = function scan(height) {
+  return this.walletdb.rescan(this.chain.db, height);
 };
 
 /**

lib/node/spvnode.js

@@ -227,16 +227,36 @@ SPVNode.prototype.rescan = function rescan() {
       this.chain.height);
   }
 
-  if (this.walletdb.height === 0)
-    return Promise.resolve(null);
-
   // Always replay the last block to make
   // sure we didn't miss anything: there
   // is no atomicity between the chaindb
   // and walletdb.
-  return this.chain.reset(this.walletdb.height - 1);
+  return this.scan();
 };
 
+/**
+ * Scan for any missed transactions.
+ * Note that this will replay the blockchain sync.
+ * @param {Number|Hash} height
+ * @returns {Promise}
+ */
+
+SPVNode.prototype.scan = co(function* scan(height) {
+  if (height == null)
+    height = this.walletdb.height;
+
+  if (typeof height === 'string') {
+    height = yield this.chain.db.getHeight(height);
+    if (height === -1)
+      return;
+  }
+
+  if (height === 0)
+    return;
+
+  yield this.chain.reset(height - 1);
+});
+
 /**
  * Broadcast a transaction (note that this will _not_ be verified
  * by the mempool - use with care, lest you get banned from