Bypass action and meta creators if payload is an Error object (#66)

* bypass action and meta creators if payload is an Error object

Author: andrewsuzuki

src/__tests__/createAction-test.js

@@ -116,5 +116,18 @@ describe('createAction()', () => {
         });
       }
     });
+
+    it('bypasses action creators if payload is an Error object', () => {
+      const actionCreator = createAction(type, () => 'not this', (_, meta) => meta);
+      const errObj = new TypeError('this is an error');
+
+      const errAction = actionCreator(errObj, { foo: 'bar' });
+      expect(errAction).to.deep.equal({
+        type,
+        payload: errObj,
+        error: true,
+        meta: { foo: 'bar' }
+      });
+    });
   });
 });

src/createAction.js

@@ -6,17 +6,20 @@ export default function createAction(type, actionCreator, metaCreator) {
   const finalActionCreator = typeof actionCreator === 'function'
     ? actionCreator
     : identity;
+
   const actionHandler = (...args) => {
+    const hasError = args[0] instanceof Error;
+
     const action = {
       type
     };
 
-    const payload = finalActionCreator(...args);
+    const payload = hasError ? args[0] : finalActionCreator(...args);
     if (!(payload === null || payload === undefined)) {
       action.payload = payload;
     }
 
-    if (action.payload instanceof Error) {
+    if (hasError) {
       // Handle FSA errors where the payload is an Error object. Set error.
       action.error = true;
     }