SSR support for class contextType

packages/react-dom/src/__tests__/ReactDOMServerIntegrationClassContextType-test.js

@@ -0,0 +1,266 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @emails react-core
+ */
+
+'use strict';
+
+const ReactDOMServerIntegrationUtils = require('./utils/ReactDOMServerIntegrationTestUtils');
+
+let React;
+let ReactDOM;
+let ReactDOMServer;
+
+function initModules() {
+  // Reset warning cache.
+  jest.resetModuleRegistry();
+  React = require('react');
+  ReactDOM = require('react-dom');
+  ReactDOMServer = require('react-dom/server');
+
+  // Make them available to the helpers.
+  return {
+    ReactDOM,
+    ReactDOMServer,
+  };
+}
+
+const {resetModules, itRenders} = ReactDOMServerIntegrationUtils(initModules);
+
+describe('ReactDOMServerIntegration', () => {
+  beforeEach(() => {
+    resetModules();
+  });
+
+  describe('class contextType', function() {
+    let PurpleContext, RedContext, Context;
+    beforeEach(() => {
+      Context = React.createContext('none');
+
+      class Parent extends React.Component {
+        render() {
+          return (
+            <Context.Provider value={this.props.text}>
+              {this.props.children}
+            </Context.Provider>
+          );
+        }
+      }
+      PurpleContext = props => <Parent text="purple">{props.children}</Parent>;
+      RedContext = props => <Parent text="red">{props.children}</Parent>;
+    });
+
+    itRenders('class child with context', async render => {
+      class ClassChildWithContext extends React.Component {
+        static contextType = Context;
+        render() {
+          const text = this.context;
+          return <div>{text}</div>;
+        }
+      }
+
+      const e = await render(
+        <PurpleContext>
+          <ClassChildWithContext />
+        </PurpleContext>,
+      );
+      expect(e.textContent).toBe('purple');
+    });
+
+    itRenders('class child without context', async render => {
+      class ClassChildWithoutContext extends React.Component {
+        render() {
+          // this should render blank; context isn't passed to this component.
+          return (
+            <div>{typeof this.context === 'string' ? this.context : ''}</div>
+          );
+        }
+      }
+
+      const e = await render(
+        <PurpleContext>
+          <ClassChildWithoutContext />
+        </PurpleContext>,
+      );
+      expect(e.textContent).toBe('');
+    });
+
+    itRenders('class child with wrong context', async render => {
+      class ClassChildWithWrongContext extends React.Component {
+        static contextType = Context;
+        render() {
+          // this should render blank; context.foo isn't passed to this component.
+          return <div id="classWrongChild">{this.context.foo}</div>;
+        }
+      }
+
+      const e = await render(
+        <PurpleContext>
+          <ClassChildWithWrongContext />
+        </PurpleContext>,
+      );
+      expect(e.textContent).toBe('');
+    });
+
+    itRenders('with context passed through to a grandchild', async render => {
+      class Grandchild extends React.Component {
+        static contextType = Context;
+        render() {
+          return <div>{this.context}</div>;
+        }
+      }
+
+      const Child = props => <Grandchild />;
+
+      const e = await render(
+        <PurpleContext>
+          <Child />
+        </PurpleContext>,
+      );
+      expect(e.textContent).toBe('purple');
+    });
+
+    itRenders('a child context overriding a parent context', async render => {
+      class Grandchild extends React.Component {
+        static contextType = Context;
+        render() {
+          return <div>{this.context}</div>;
+        }
+      }
+
+      const e = await render(
+        <PurpleContext>
+          <RedContext>
+            <Grandchild />
+          </RedContext>
+        </PurpleContext>,
+      );
+      expect(e.textContent).toBe('red');
+    });
+
+    itRenders('multiple contexts', async render => {
+      const Theme = React.createContext('dark');
+      const Language = React.createContext('french');
+      class Parent extends React.Component {
+        render() {
+          return (
+            <Theme.Provider value="light">
+              <Child />
+            </Theme.Provider>
+          );
+        }
+      }
+
+      function Child() {
+        return (
+          <Language.Provider value="english">
+            <Grandchild />
+          </Language.Provider>
+        );
+      }
+
+      class ThemeComponent extends React.Component {
+        static contextType = Theme;
+        render() {
+          return <div id="theme">{this.context}</div>;
+        }
+      }
+
+      class LanguageComponent extends React.Component {
+        static contextType = Language;
+        render() {
+          return <div id="language">{this.context}</div>;
+        }
+      }
+
+      const Grandchild = props => {
+        return (
+          <div>
+            <ThemeComponent />
+            <LanguageComponent />
+          </div>
+        );
+      };
+
+      const e = await render(<Parent />);
+      expect(e.querySelector('#theme').textContent).toBe('light');
+      expect(e.querySelector('#language').textContent).toBe('english');
+    });
+
+    itRenders('nested context unwinding', async render => {
+      const Theme = React.createContext('dark');
+      const Language = React.createContext('french');
+
+      class ThemeConsumer extends React.Component {
+        static contextType = Theme;
+        render() {
+          return this.props.children(this.context);
+        }
+      }
+
+      class LanguageConsumer extends React.Component {
+        static contextType = Language;
+        render() {
+          return this.props.children(this.context);
+        }
+      }
+
+      const App = () => (
+        <div>
+          <Theme.Provider value="light">
+            <Language.Provider value="english">
+              <Theme.Provider value="dark">
+                <ThemeConsumer>
+                  {theme => <div id="theme1">{theme}</div>}
+                </ThemeConsumer>
+              </Theme.Provider>
+              <ThemeConsumer>
+                {theme => <div id="theme2">{theme}</div>}
+              </ThemeConsumer>
+              <Language.Provider value="sanskrit">
+                <Theme.Provider value="blue">
+                  <Theme.Provider value="red">
+                    <LanguageConsumer>
+                      {() => (
+                        <Language.Provider value="chinese">
+                          <Language.Provider value="hungarian" />
+                          <LanguageConsumer>
+                            {language => <div id="language1">{language}</div>}
+                          </LanguageConsumer>
+                        </Language.Provider>
+                      )}
+                    </LanguageConsumer>
+                  </Theme.Provider>
+                  <LanguageConsumer>
+                    {language => (
+                      <React.Fragment>
+                        <ThemeConsumer>
+                          {theme => <div id="theme3">{theme}</div>}
+                        </ThemeConsumer>
+                        <div id="language2">{language}</div>
+                      </React.Fragment>
+                    )}
+                  </LanguageConsumer>
+                </Theme.Provider>
+              </Language.Provider>
+            </Language.Provider>
+          </Theme.Provider>
+          <LanguageConsumer>
+            {language => <div id="language3">{language}</div>}
+          </LanguageConsumer>
+        </div>
+      );
+      let e = await render(<App />);
+      expect(e.querySelector('#theme1').textContent).toBe('dark');
+      expect(e.querySelector('#theme2').textContent).toBe('light');
+      expect(e.querySelector('#theme3').textContent).toBe('blue');
+      expect(e.querySelector('#language1').textContent).toBe('chinese');
+      expect(e.querySelector('#language2').textContent).toBe('sanskrit');
+      expect(e.querySelector('#language3').textContent).toBe('french');
+    });
+  });
+});

packages/react-dom/src/server/ReactPartialRenderer.js

@@ -180,6 +180,7 @@ const didWarnAboutBadClass = {};
 const didWarnAboutDeprecatedWillMount = {};
 const didWarnAboutUndefinedDerivedState = {};
 const didWarnAboutUninitializedState = {};
+const didWarnAboutInvalidateContextType = {};
 const valuePropNames = ['value', 'defaultValue'];
 const newlineEatingTags = {
   listing: true,
@@ -357,13 +358,33 @@ function checkContextTypes(typeSpecs, values, location: string) {
 }
 
 function processContext(type, context) {
-  const maskedContext = maskContext(type, context);
-  if (__DEV__) {
-    if (type.contextTypes) {
-      checkContextTypes(type.contextTypes, maskedContext, 'context');
+  const contextType = type.contextType;
+  if (typeof contextType === 'object' && contextType !== null) {
+    if (__DEV__) {
+      if (contextType.$$typeof !== REACT_CONTEXT_TYPE) {
+        let name = getComponentName(type);
+        if (!didWarnAboutInvalidateContextType[name]) {
+          didWarnAboutInvalidateContextType[type] = true;
+          warningWithoutStack(
+            false,
+            '%s defines an invalid contextType. ' +
+              'contextType should point to the Context object returned by React.createContext(). ' +
+              'Did you accidentally pass the Context.Provider instead?',
+            name || 'Component',
+          );
+        }
+      }
     }
+    return contextType._currentValue;
+  } else {
+    const maskedContext = maskContext(type, context);
+    if (__DEV__) {
+      if (type.contextTypes) {
+        checkContextTypes(type.contextTypes, maskedContext, 'context');
+      }
+    }
+    return maskedContext;
   }
-  return maskedContext;
 }
 
 const hasOwnProperty = Object.prototype.hasOwnProperty;

packages/react-reconciler/src/ReactFiberClassComponent.js

@@ -25,9 +25,11 @@ import shallowEqual from 'shared/shallowEqual';
 import getComponentName from 'shared/getComponentName';
 import invariant from 'shared/invariant';
 import warningWithoutStack from 'shared/warningWithoutStack';
+import {REACT_CONTEXT_TYPE} from 'shared/ReactSymbols';
 
 import {startPhaseTimer, stopPhaseTimer} from './ReactDebugFiberPerf';
 import {StrictMode} from './ReactTypeOfMode';
+
 import {
   enqueueUpdate,
   processUpdateQueue,
@@ -516,7 +518,7 @@ function constructClassInstance(
   if (typeof contextType === 'object' && contextType !== null) {
     if (__DEV__) {
       if (
-        contextType.Consumer === undefined &&
+        contextType.$$typeof !== REACT_CONTEXT_TYPE &&
         !didWarnAboutInvalidateContextType.has(ctor)
       ) {
         didWarnAboutInvalidateContextType.add(ctor);