optimize activity check for single address

lib/blockchainexplorers/insight.js

@@ -1,6 +1,7 @@
 'use strict';
 
 var _ = require('lodash');
+var async = require('async');
 var $ = require('preconditions').singleton();
 var log = require('npmlog');
 log.debug = log.verbose;
@@ -114,8 +115,10 @@ Insight.prototype.getTransactions = function(addresses, from, to, cb) {
 };
 
 Insight.prototype.getAddressActivity = function(addresses, cb) {
-  function getOneAddressActivity(address, cb) {
-    var url = this.url + this.apiPrefix + '/addr/' + address;
+  var self = this;
+
+  function getOneAddressActivity(address, cb2) {
+    var url = self.url + self.apiPrefix + '/addr/' + address;
     var args = {
       method: 'GET',
       url: url,
@@ -123,21 +126,26 @@ Insight.prototype.getAddressActivity = function(addresses, cb) {
     };
 
     request(args, function(err, res, result) {
-      if (res && res.statusCode == 404) return cb();
+      if (res && res.statusCode == 404) return cb2();
       if (err || res.statusCode !== 200)
-        return cb(_parseErr(err, res));
+        return cb2(_parseErr(err, res));
 
       var nbTxs = result.unconfirmedTxApperances + result.txApperances;
-      return cb(null, nbTxs > 0);
+      return cb2(null, nbTxs > 0);
     });
   };
 
   addresses = [].concat(addresses);
+
+  if (addresses.length == 1) {
+    return getOneAddressActivity(addresses[0], cb);
+  }
+
   var activityFound = false;
   var i = 0;
 
   async.until(function() {
-    return activityFound;
+    return i == addresses.length || activityFound;
   }, function(next) {
     getOneAddressActivity(addresses[i++], function(err, res) {
       if (err) return next(err);