diff --git a/packages/observe-sequence/observe_sequence.js b/packages/observe-sequence/observe_sequence.js
index fd4a591c3..b0fc256c6 100644
--- a/packages/observe-sequence/observe_sequence.js
+++ b/packages/observe-sequence/observe_sequence.js
@@ -2,14 +2,16 @@ const isObject = function (value) {
   var type = typeof value;
   return value != null && (type == 'object' || type == 'function');
 }
-const has = function (obj, key) {
-  var keyParts = key.split('.');
-
-  return !!obj && (
-    keyParts.length > 1
-      ? has(obj[key.split('.')[0]], keyParts.slice(1).join('.'))
-      : hasOwnProperty.call(obj, key)
-  );
+const has = (obj, path) => {
+  const thisPath = Array.isArray(path) ? path : [path];
+  const length = thisPath.length;
+  for (let i = 0; i < length; i++) {
+    const key = thisPath[i];
+    const _has = obj != null && Object.hasOwnProperty.call(obj, key);
+    if (!_has) return false;
+    obj = obj[key];
+  }
+  return !!length;
 };
 
 const warn = function () {
diff --git a/packages/observe-sequence/observe_sequence_tests.js b/packages/observe-sequence/observe_sequence_tests.js
index 7f62a0f47..a0e91dc58 100644
--- a/packages/observe-sequence/observe_sequence_tests.js
+++ b/packages/observe-sequence/observe_sequence_tests.js
@@ -476,7 +476,7 @@ Tinytest.add('observe-sequence - cursor to null', function (test) {
 Tinytest.add('observe-sequence - cursor to array', function (test) {
   var dep = new Tracker.Dependency;
   var coll = new Mongo.Collection(null);
-  coll.insert({_id: "13", foo: 1});
+  coll.insert({_id: "13.5", foo: 1});
   var cursor = coll.find({}, {sort: {_id: 1}});
   var seq = cursor;
 
@@ -485,14 +485,14 @@ Tinytest.add('observe-sequence - cursor to array', function (test) {
     return seq;
   }, function () {
     coll.insert({_id: "37", bar: 2});
-    seq = [{_id: "13", foo: 1}, {_id: "38", bar: 2}];
+    seq = [{_id: "13.5", foo: 1}, {_id: "38", bar: 2}];
     dep.changed();
   }, [
-    {addedAt: ["13", {_id: "13", foo: 1}, 0, null]},
+    {addedAt: ["13.5", {_id: "13.5", foo: 1}, 0, null]},
     {addedAt: ["37", {_id: "37", bar: 2}, 1, null]},
     {removedAt: ["37", {_id: "37", bar: 2}, 1]},
     {addedAt: ["38", {_id: "38", bar: 2}, 1, null]},
-    {changedAt: ["13", {_id: "13", foo: 1}, {_id: "13", foo: 1}, 0]}
+    {changedAt: ["13.5", {_id: "13.5", foo: 1}, {_id: "13.5", foo: 1}, 0]}
   ]);
 });