Merge pull request #189 from planetcohen/fix-xxxToProps-length-check

fix length comparisons on xxxToProps functions

Author: gaearon

src/components/connect.js

@@ -28,8 +28,8 @@ export default function connect(mapStateToProps, mapDispatchToProps, mergeProps,
     wrapActionCreators(mapDispatchToProps) :
     mapDispatchToProps || defaultMapDispatchToProps
   const finalMergeProps = mergeProps || defaultMergeProps
-  const shouldUpdateStateProps = finalMapStateToProps.length > 1
-  const shouldUpdateDispatchProps = finalMapDispatchToProps.length > 1
+  const shouldUpdateStateProps = finalMapStateToProps.length !== 1
+  const shouldUpdateDispatchProps = finalMapDispatchToProps.length !== 1
   const { pure = true, withRef = false } = options
 
   // Helps track hot reloading.

test/components/connect.spec.js

@@ -426,10 +426,12 @@ describe('React', () => {
 
       let invocationCount = 0
 
-      @connect(() => {
+      /*eslint-disable no-unused-vars */
+      @connect((arg1) => {
         invocationCount++
         return {}
       })
+      /*eslint-enable no-unused-vars */
       class WithoutProps extends Component {
         render() {
           return <Passthrough {...this.props}/>
@@ -467,6 +469,53 @@ describe('React', () => {
       expect(invocationCount).toEqual(2)
     })
 
+    it('should invoke mapState every time props are changed if it has zero arguments', () => {
+      const store = createStore(stringBuilder)
+
+      let invocationCount = 0
+
+      @connect(() => {
+        invocationCount++
+        return {}
+      })
+
+      class WithoutProps extends Component {
+        render() {
+          return <Passthrough {...this.props}/>
+        }
+      }
+
+      class OuterComponent extends Component {
+        constructor() {
+          super()
+          this.state = { foo: 'FOO' }
+        }
+
+        setFoo(foo) {
+          this.setState({ foo })
+        }
+
+        render() {
+          return (
+            <div>
+              <WithoutProps {...this.state} />
+            </div>
+          )
+        }
+      }
+
+      let outerComponent
+      TestUtils.renderIntoDocument(
+        <ProviderMock store={store}>
+          <OuterComponent ref={c => outerComponent = c} />
+        </ProviderMock>
+      )
+      outerComponent.setFoo('BAR')
+      outerComponent.setFoo('DID')
+
+      expect(invocationCount).toEqual(4)
+    })
+
     it('should invoke mapState every time props are changed if it has a second argument', () => {
       const store = createStore(stringBuilder)
 
@@ -524,10 +573,12 @@ describe('React', () => {
 
       let invocationCount = 0
 
-      @connect(null, () => {
+      /*eslint-disable no-unused-vars */
+      @connect(null, (arg1) => {
         invocationCount++
         return {}
       })
+      /*eslint-enable no-unused-vars */
       class WithoutProps extends Component {
         render() {
           return <Passthrough {...this.props}/>
@@ -566,6 +617,54 @@ describe('React', () => {
       expect(invocationCount).toEqual(1)
     })
 
+    it('should invoke mapDispatch every time props are changed if it has zero arguments', () => {
+      const store = createStore(stringBuilder)
+
+      let invocationCount = 0
+
+      @connect(null, () => {
+        invocationCount++
+        return {}
+      })
+
+      class WithoutProps extends Component {
+        render() {
+          return <Passthrough {...this.props}/>
+        }
+      }
+
+      class OuterComponent extends Component {
+        constructor() {
+          super()
+          this.state = { foo: 'FOO' }
+        }
+
+        setFoo(foo) {
+          this.setState({ foo })
+        }
+
+        render() {
+          return (
+            <div>
+              <WithoutProps {...this.state} />
+            </div>
+          )
+        }
+      }
+
+      let outerComponent
+      TestUtils.renderIntoDocument(
+        <ProviderMock store={store}>
+          <OuterComponent ref={c => outerComponent = c} />
+        </ProviderMock>
+      )
+
+      outerComponent.setFoo('BAR')
+      outerComponent.setFoo('DID')
+
+      expect(invocationCount).toEqual(3)
+    })
+
     it('should invoke mapDispatch every time props are changed if it has a second argument', () => {
       const store = createStore(stringBuilder)