change fee sampling

lib/server.js

@@ -752,23 +752,22 @@ WalletService.prototype.getBalance = function(opts, cb) {
 WalletService.prototype._sampleFeeLevels = function(network, points, cb) {
   var self = this;
 
-  // TODO: cache blockexplorer data
   var bc = self._getBlockchainExplorer(network);
-  async.map(points, function(p, next) {
-    bc.estimateFee(p, function(err, result) {
+  bc.estimateFee(points, function(err, result) {
     if (err) {
       log.error('Error estimating fee', err);
-        return next(err);
+      return cb(err);
     }
-      var feePerKB = _.isObject(result) ? +(result.feePerKB) : -1;
+
+    var levels = _.zipObject(_.map(points, function(p) {
+      var feePerKB = _.isObject(result) ? +result[p] : -1;
       if (feePerKB < 0) {
         log.warn('Could not compute fee estimation (nbBlocks=' + p + ')');
       }
-      return next(null, [p, Utils.strip(feePerKB * 1e8)]);
-    });
-  }, function(err, results) {
-    if (err) return cb(err);
-    return cb(null, _.zipObject(results));
+      return [p, Utils.strip(feePerKB * 1e8)];
+    }));
+
+    return cb(null, levels);
   });
 };