Mock SCU if gDSFP defined in shallow renderer rerender

enzymejs · Feb 28, 2019 · cffd5b0 · cffd5b0
1 parent 6fda886
commit cffd5b0
Showing 1 changed file with 27 additions and 0 deletions.
diff --git a/packages/enzyme/src/ShallowWrapper.js b/packages/enzyme/src/ShallowWrapper.js
@@ -243,6 +243,29 @@ function privateSetChildContext(adapter, wrapper, instance, renderedNode, getChi
   }
 }
 
+function mockSCUIfgDSFPReturnNonNull(node, props, state) {
+  const { getDerivedStateFromProps } = node.type;
+  const { instance } = node;
+  if (typeof getDerivedStateFromProps === 'function') {
+    const gDSFPResult = getDerivedStateFromProps(props, state);
+    if (gDSFPResult != null) {
+      // we try to fix a React shallow renderer bug here.
+      // (facebook/react#14607, which has been fixed in react 16.8):
+      // when gDSFP return derived state, it will set instance state in shallow renderer before SCU,
+      // this will cause `this.state` in sCU be the updated state, which is wrong behavior.
+      // so we have to wrap sCU to pass the old state to original sCU.
+      const originalSCU = instance.shouldComponentUpdate;
+      instance.shouldComponentUpdate = (...args) => {
+        instance.state = state;
+        const sCUResult = originalSCU.apply(instance, args);
+        const nextState = args[1];
+        instance.state = nextState;
+        instance.shouldComponentUpdate = originalSCU;
+        return sCUResult;
+      };
+    }
+  }
+}
 
 /**
  * @class ShallowWrapper
@@ -452,6 +475,8 @@ class ShallowWrapper {
             && instance
           ) {
             if (typeof instance.shouldComponentUpdate === 'function') {
+              const nextProps = { ...prevProps, ...props };
+              mockSCUIfgDSFPReturnNonNull(node, nextProps, state, instance);
               shouldComponentUpdateSpy = spyMethod(instance, 'shouldComponentUpdate');
             }
             if (
@@ -601,6 +626,8 @@ class ShallowWrapper {
             && lifecycles.componentDidUpdate.onSetState
             && typeof instance.shouldComponentUpdate === 'function'
           ) {
+            const props = prevProps;
+            mockSCUIfgDSFPReturnNonNull(node, props, state, instance);
             shouldComponentUpdateSpy = spyMethod(instance, 'shouldComponentUpdate');
           }
           if (