diff --git a/lib/bcoin/utils.js b/lib/bcoin/utils.js
index b1eab1b8..4a35ad17 100644
--- a/lib/bcoin/utils.js
+++ b/lib/bcoin/utils.js
@@ -2683,9 +2683,13 @@ utils.serial = function serial(stack, callback) {
 
 utils.toMap = function toMap(obj) {
   var map = {};
-  obj.forEach(function(value) {
+  var i, value;
+
+  for (i = 0; i < obj.length; i++) {
+    value = obj[i];
     map[value] = true;
-  });
+  }
+
   return map;
 };
 
@@ -2697,9 +2701,14 @@ utils.toMap = function toMap(obj) {
 
 utils.revMap = function revMap(map) {
   var reversed = {};
-  Object.keys(map).forEach(function(key) {
+  var keys = Object.keys(map);
+  var i, key;
+
+  for (i = 0; i < keys.length; i++) {
+    key = keys[i];
     reversed[map[key]] = key;
-  });
+  }
+
   return reversed;
 };