diff --git a/src/ol/extent/index.js b/src/ol/extent/index.js
index 451f27d8d2..70e0a2d55c 100644
--- a/src/ol/extent/index.js
+++ b/src/ol/extent/index.js
@@ -1,23 +1,9 @@
 goog.provide('ol.extent');
-goog.provide('ol.extent.Relationship');
 
 goog.require('ol');
 goog.require('ol.asserts');
 goog.require('ol.extent.Corner');
-
-
-/**
- * Relationship to an extent.
- * @enum {number}
- */
-ol.extent.Relationship = {
-  UNKNOWN: 0,
-  INTERSECTING: 1,
-  ABOVE: 2,
-  RIGHT: 4,
-  BELOW: 8,
-  LEFT: 16
-};
+goog.require('ol.extent.Relationship');
 
 
 /**
diff --git a/src/ol/extent/relationship.js b/src/ol/extent/relationship.js
new file mode 100644
index 0000000000..ac359b3661
--- /dev/null
+++ b/src/ol/extent/relationship.js
@@ -0,0 +1,15 @@
+goog.provide('ol.extent.Relationship');
+
+
+/**
+ * Relationship to an extent.
+ * @enum {number}
+ */
+ol.extent.Relationship = {
+  UNKNOWN: 0,
+  INTERSECTING: 1,
+  ABOVE: 2,
+  RIGHT: 4,
+  BELOW: 8,
+  LEFT: 16
+};