Merge pull request immutable-js#381 from jeffbski/subCursor-fix

leebyron · leebyron · commit 577c9a0643bc · 2015-03-27T05:31:53.000+01:00
subCursor (cursor.cursor('a')) returns improper type
diff --git a/contrib/cursor/__tests__/Cursor.ts b/contrib/cursor/__tests__/Cursor.ts
@@ -49,6 +49,13 @@ describe('Cursor', () => {
     expect(deepCursor.deref()).toBe(data.getIn(Immutable.fromJS(['a', 'b'])));
   });
 
+  it('cursor return new cursors of correct type', () => {
+    var data = Immutable.fromJS({ a: [1, 2, 3] });
+    var cursor = Cursor.from(data);
+    var deepCursor = <any>cursor.cursor('a');
+    expect(deepCursor.findIndex).toBeDefined();
+  });
+
   it('can be treated as a value', () => {
     var data = Immutable.fromJS(json);
     var cursor = Cursor.from(data, ['a', 'b']);
diff --git a/contrib/cursor/index.js b/contrib/cursor/index.js
@@ -233,6 +233,13 @@ function wrappedValue(cursor, keyPath, value) {
 }
 
 function subCursor(cursor, keyPath, value) {
+  if (arguments.length < 3) {
+    return makeCursor( // call without value
+      cursor._rootData,
+      newKeyPath(cursor._keyPath, keyPath),
+      cursor._onChange
+    );
+  }
   return makeCursor(
     cursor._rootData,
     newKeyPath(cursor._keyPath, keyPath),
