Merge cbd93b0 into 3cb22fa

Changelog.md

@@ -2,6 +2,8 @@
 
 ### vNext
 
+* Fix React Component detection bug in `getDataFromTree` [#1604](https://github.com/apollographql/react-apollo/pull/1604)
+
 ### 2.1.0-beta.0
 
 * Beta release of all 2.1 features!

src/getDataFromTree.ts

@@ -59,7 +59,7 @@ export function walkTree<Cache>(
 
     // Are we are a react class?
     //   https://github.com/facebook/react/blob/master/src/renderers/shared/stack/reconciler/ReactCompositeComponent.js#L66
-    if (Component.prototype && Component.prototype.render) {
+    if (Component.prototype && (Component.prototype.render || Component.prototype.isReactComponent)) {
       // typescript force casting since typescript doesn't have definitions for class
       // methods
       const _component = Component as any;

test/server/getDataFromTree.test.tsx

@@ -268,6 +268,20 @@ describe('SSR', () => {
         );
         expect(elementCount).toEqual(9);
       });
+
+      it('basic classes with render on instance', () => {
+        let elementCount = 0;
+        class MyComponent extends (React.Component as any) {
+          render = () => {
+            return <div>{_.times(this.props.n, i => <span key={i} />)}</div>;
+          }
+        }
+        const MyCompAsAny = MyComponent as any;
+        walkTree(<MyCompAsAny n={5} />, {}, element => {
+          elementCount += 1;
+        });
+        expect(elementCount).toEqual(7);
+      });
     });
   });