Omit payload on undefined only (#128)

Author: timche

src/__tests__/createAction-test.js

@@ -93,11 +93,6 @@ describe('createAction()', () => {
         type
       });
 
-      const explictNullAction = createAction(type)(null);
-      expect(explictNullAction).to.deep.equal({
-        type
-      });
-
       const baz = '1';
       const actionCreator = createAction(type, null, () => ({ bar: baz }));
       expect(actionCreator()).to.deep.equal({

src/createAction.js

@@ -1,4 +1,5 @@
 import identity from 'lodash/identity';
+import isUndefined from 'lodash/isUndefined';
 
 export default function createAction(type, payloadCreator, metaCreator) {
   const finalPayloadCreator = typeof payloadCreator === 'function'
@@ -13,7 +14,7 @@ export default function createAction(type, payloadCreator, metaCreator) {
     };
 
     const payload = hasError ? args[0] : finalPayloadCreator(...args);
-    if (!(payload === null || payload === undefined)) {
+    if (!isUndefined(payload)) {
       action.payload = payload;
     }