Use old school ES5 just in case

Author: adamreisnz

lib/document.js

@@ -2595,13 +2595,13 @@ Document.prototype.depopulate = function(path) {
   if (typeof path === 'string') {
     path = path.split(' ');
   }
-  for (const p of path) {
-    var populatedIds = this.populated(p);
+  for (var i = 0; i < path.length; i++) {
+    var populatedIds = this.populated(path[i]);
     if (!populatedIds) {
       continue;
     }
-    delete this.$__.populated[p];
-    this.$set(p, populatedIds);
+    delete this.$__.populated[path[i]];
+    this.$set(path[i], populatedIds);
   }
   return this;
 };