didierfranc#99 state is not updated when nothing is returned

src/__test__/__snapshots__/index.test.js.snap

@@ -9,3 +9,7 @@ exports[`render provider with its children 1`] = `
  Children
 </h1>
 `;
+
+exports[`state is not updated when nothing is returned 1`] = `"0"`;
+
+exports[`state is not updated when nothing is returned 2`] = `"2"`;

src/__test__/index.test.js

@@ -20,6 +20,7 @@ beforeEach(() => {
  const { stars } = await fakeFetch()
  return { stars }
  },
+ doNothing: () => {},
  },
  }
 
@@ -128,3 +129,40 @@ test('connect(): allow ownprops from mapStateToProps', async () => {
  const instance = tree.root.findByType(Stars).children[0]
  expect(instance.props.stars).toBe(20000)
 })
+
+test('state is not updated when nothing is returned', async () => {
+ const { Provider, connect, actions } = store
+ const didUpdateSpy = jest.fn()
+
+ /* eslint-disable react/no-multi-comp,react/prop-types */
+ class Count extends React.PureComponent {
+ componentDidUpdate() {
+ didUpdateSpy()
+ }
+
+ render() {
+ return this.props.count
+ }
+ }
+ const ConnectedCount = connect(({ count }) => ({ count }))(Count)
+ /* eslint-enable */
+
+ const App = () => (
+ <Provider>
+ <ConnectedCount />
+ </Provider>
+ )
+ const tree = renderer.create(<App />)
+
+ const instance = tree.root.findByType(ConnectedCount).children[0]
+ instance.componentDidUpdate = jest.fn()
+ expect(tree.toJSON()).toMatchSnapshot()
+
+ await actions.increment()
+ expect(didUpdateSpy).toHaveBeenCalledTimes(1)
+ await actions.increment()
+ expect(didUpdateSpy).toHaveBeenCalledTimes(2)
+ actions.doNothing()
+ expect(didUpdateSpy).toHaveBeenCalledTimes(2)
+ expect(tree.toJSON()).toMatchSnapshot()
+})

src/index.js

@@ -46,6 +46,9 @@ const createStore: CreateStore = (
  let state = initialState
 
  const setState: CustomSetState = (action, result, ...args) => {
+ if (typeof result === 'undefined') {
+ return Promise.resolve()
+ }
  state = { ...state, ...result }
  return new Promise(resolve => {
  const subscriptions = getSubscriptions()
@@ -68,7 +71,7 @@ const createStore: CreateStore = (
 
  const result = actionsCreators[v](state, actions, ...args)
 
- return result.then
+ return (typeof result === 'object' && result.then)
  ? result.then(result => setState(v, result, ...args))
  : setState(v, result, ...args)
  },