diff --git a/src/ol/source/source.js b/src/ol/source/source.js
index acfd9b21fa..6fd4cdf57f 100644
--- a/src/ol/source/source.js
+++ b/src/ol/source/source.js
@@ -1,22 +1,10 @@
 goog.provide('ol.source.Source');
-goog.provide('ol.source.State');
 
 goog.require('ol');
 goog.require('ol.Attribution');
 goog.require('ol.Object');
 goog.require('ol.proj');
-
-
-/**
- * State of the source, one of 'undefined', 'loading', 'ready' or 'error'.
- * @enum {string}
- */
-ol.source.State = {
-  UNDEFINED: 'undefined',
-  LOADING: 'loading',
-  READY: 'ready',
-  ERROR: 'error'
-};
+goog.require('ol.source.State');
 
 
 /**
diff --git a/src/ol/source/state.js b/src/ol/source/state.js
new file mode 100644
index 0000000000..e53aa054d2
--- /dev/null
+++ b/src/ol/source/state.js
@@ -0,0 +1,14 @@
+goog.provide('ol.source.State');
+
+
+/**
+ * State of the source, one of 'undefined', 'loading', 'ready' or 'error'.
+ * @enum {string}
+ */
+ol.source.State = {
+  UNDEFINED: 'undefined',
+  LOADING: 'loading',
+  READY: 'ready',
+  ERROR: 'error'
+};
+