don't swallow async errors in sync generator

Author: alexeyraspopov

modules/Coroutine.js

@@ -76,7 +76,9 @@ function create(asyncFn) {
 function resolveSyncIterator(i, step, cb) {
   if (!step.done) {
     if (isPromiseLike(step.value)) {
-      return step.value.then(data => resolveSyncIterator(i, i.next(data), cb));
+      return step.value
+        .then(data => resolveSyncIterator(i, i.next(data), cb))
+        .catch(error => resolveSyncIterator(i, i.throw(error), cb));
     } else {
       return resolveSyncIterator(i, i.next(step.value), cb);
     }

modules/__tests__/Coroutine-test.js

@@ -62,6 +62,22 @@ describe('Coroutine', () => {
     expect(tree.toJSON()).toEqual(result.toJSON());
   });
 
+  it('should rethrow exceptions back to generator', async () => {
+    function* render() {
+      try {
+        yield Promise.reject(new Error('Boom'));
+      } catch (error) {
+        return <p>{error.message}</p>;
+      }
+    }
+
+    let TestComponent = Coroutine.create(render);
+    let tree = await Renderer.create(<TestComponent />);
+
+    let result = await Renderer.create(<p>Boom</p>);
+    expect(tree.toJSON()).toEqual(result.toJSON());
+  });
+
   it('should restart coroutine on new props', async () => {
     let getData = jest.fn(n => Promise.resolve(n * 2));
     let trap = jest.fn();