Basic shallow rendering support

src/core/ReactCompositeComponent.js

@@ -650,6 +650,25 @@ var ReactCompositeComponentMixin = assign({},
     }
   },
 
+  /**
+   * @private
+   */
+  _renderValidatedComponentWithoutOwnerOrContext: function() {
+    var inst = this._instance;
+    var renderedComponent = inst.render();
+    if (__DEV__) {
+      // We allow auto-mocks to proceed as if they're returning null.
+      if (typeof renderedComponent === 'undefined' &&
+          inst.render._isMockFunction) {
+        // This is probably bad practice. Consider warning here and
+        // deprecating this convenience.
+        renderedComponent = null;
+      }
+    }
+
+    return renderedComponent;
+  },
+
   /**
    * @private
    */
@@ -665,16 +684,8 @@ var ReactCompositeComponentMixin = assign({},
       ReactCurrentOwner.current = this;
       var inst = this._instance;
       try {
-        renderedComponent = inst.render();
-        if (__DEV__) {
-          // We allow auto-mocks to proceed as if they're returning null.
-          if (typeof renderedComponent === 'undefined' &&
-              inst.render._isMockFunction) {
-            // This is probably bad practice. Consider warning here and
-            // deprecating this convenience.
-            renderedComponent = null;
-          }
-        }
+        renderedComponent =
+          this._renderValidatedComponentWithoutOwnerOrContext();
       } finally {
         ReactContext.current = previousContext;
         ReactCurrentOwner.current = null;
@@ -734,11 +745,124 @@ var ReactCompositeComponentMixin = assign({},
 
 });
 
+var ShallowMixin = assign({},
+  ReactCompositeComponentMixin, {
+
+  /**
+   * Initializes the component, renders markup, and registers event listeners.
+   *
+   * @param {string} rootID DOM ID of the root node.
+   * @param {ReactReconcileTransaction|ReactServerRenderingTransaction} transaction
+   * @param {number} mountDepth number of components in the owner hierarchy
+   * @return {ReactElement} Shallow rendering of the component.
+   * @final
+   * @internal
+   */
+  mountComponent: function(rootID, transaction, mountDepth) {
+    ReactComponent.Mixin.mountComponent.call(
+      this,
+      rootID,
+      transaction,
+      mountDepth
+    );
+
+    var inst = this._instance;
+
+    // Store a reference from the instance back to the internal representation
+    ReactInstanceMap.set(inst, this);
+
+    this._compositeLifeCycleState = CompositeLifeCycle.MOUNTING;
+
+    // No context for shallow-mounted components.
+    inst.props = this._processProps(this._currentElement.props);
+
+    var initialState = inst.getInitialState ? inst.getInitialState() : null;
+    if (__DEV__) {
+      // We allow auto-mocks to proceed as if they're returning null.
+      if (typeof initialState === 'undefined' &&
+          inst.getInitialState._isMockFunction) {
+        // This is probably bad practice. Consider warning here and
+        // deprecating this convenience.
+        initialState = null;
+      }
+    }
+    invariant(
+      typeof initialState === 'object' && !Array.isArray(initialState),
+      '%s.getInitialState(): must return an object or null',
+      inst.constructor.displayName || 'ReactCompositeComponent'
+    );
+    inst.state = initialState;
+
+    this._pendingState = null;
+    this._pendingForceUpdate = false;
+
+    if (inst.componentWillMount) {
+      inst.componentWillMount();
+      // When mounting, calls to `setState` by `componentWillMount` will set
+      // `this._pendingState` without triggering a re-render.
+      if (this._pendingState) {
+        inst.state = this._pendingState;
+        this._pendingState = null;
+      }
+    }
+
+    // No recursive call to instantiateReactComponent for shallow rendering.
+    this._renderedComponent =
+      this._renderValidatedComponentWithoutOwnerOrContext();
+
+    // Done with mounting, `setState` will now trigger UI changes.
+    this._compositeLifeCycleState = null;
+
+    // No call to this._renderedComponent.mountComponent for shallow
+    // rendering.
+
+    if (inst.componentDidMount) {
+      transaction.getReactMountReady().enqueue(inst.componentDidMount, inst);
+    }
+
+    return this._renderedComponent;
+  },
+
+  /**
+   * Call the component's `render` method and update the DOM accordingly.
+   *
+   * @param {ReactReconcileTransaction} transaction
+   * @internal
+   */
+  _updateRenderedComponent: function(transaction) {
+    var prevComponentInstance = this._renderedComponent;
+    var prevRenderedElement = prevComponentInstance._currentElement;
+    // Use the without-owner-or-context variant of _rVC below:
+    var nextRenderedElement = this._renderValidatedComponentWithoutOwnerOrContext();
+    if (shouldUpdateReactComponent(prevRenderedElement, nextRenderedElement)) {
+      prevComponentInstance.receiveComponent(
+        nextRenderedElement,
+        transaction
+      );
+    } else {
+      // These two IDs are actually the same! But nothing should rely on that.
+      var thisID = this._rootNodeID;
+      var prevComponentID = prevComponentInstance._rootNodeID;
+      // Don't unmount previous instance since it was never mounted, due to
+      // shallow render.
+      //prevComponentInstance.unmountComponent();
+      this._renderedComponent = nextRenderedElement;
+      // ^ no instantiateReactComponent
+      //
+      // no recursive mountComponent
+      return nextRenderedElement;
+    }
+  }
+
+});
+
 var ReactCompositeComponent = {
 
   LifeCycle: CompositeLifeCycle,
 
-  Mixin: ReactCompositeComponentMixin
+  Mixin: ReactCompositeComponentMixin,
+
+  ShallowMixin: ShallowMixin
 
 };
 

src/core/ReactElement.js

@@ -106,7 +106,21 @@ var ReactElement = function(type, key, ref, owner, context, props) {
     // an external backing store so that we can freeze the whole object.
     // This can be replaced with a WeakMap once they are implemented in
     // commonly used development environments.
-    this._store = { validated: false, props: props };
+    this._store = { props: props };
+
+    // To make comparing ReactElements easier for testing purposes, we make
+    // the validation flag non-enumerable (where possible, which should
+    // include every environment we run tests in), so the test framework
+    // ignores it.
+    try {
+      Object.defineProperty(this._store, 'validated', {
+        configurable: false,
+        enumerable: false,
+        writable: true
+      });
+    } catch (x) {
+    }
+    this._store.validated = false;
 
     // We're not allowed to set props directly on the object so we early
     // return and rely on the prototype membrane to forward to the backing

src/test/ReactTestUtils.js

@@ -17,12 +17,15 @@ var EventPropagators = require('EventPropagators');
 var React = require('React');
 var ReactElement = require('ReactElement');
 var ReactBrowserEventEmitter = require('ReactBrowserEventEmitter');
+var ReactCompositeComponent = require('ReactCompositeComponent');
+var ReactInstanceHandles = require('ReactInstanceHandles');
 var ReactInstanceMap = require('ReactInstanceMap');
 var ReactMount = require('ReactMount');
 var ReactUpdates = require('ReactUpdates');
 var SyntheticEvent = require('SyntheticEvent');
 
 var assign = require('Object.assign');
+var instantiateReactComponent = require('instantiateReactComponent');
 
 var topLevelTypes = EventConstants.topLevelTypes;
 
@@ -298,10 +301,53 @@ var ReactTestUtils = {
     };
   },
 
+  createRenderer: function() {
+    return new ReactShallowRenderer();
+  },
+
   Simulate: null,
   SimulateNative: {}
 };
 
+/**
+ * @class ReactShallowRenderer
+ */
+var ReactShallowRenderer = function() {
+  this._instance = null;
+};
+
+ReactShallowRenderer.prototype.getRenderOutput = function() {
+  return (this._instance && this._instance._renderedComponent) || null;
+};
+
+var ShallowComponentWrapper = function(inst) {
+  this._instance = inst;
+}
+assign(
+  ShallowComponentWrapper.prototype,
+  ReactCompositeComponent.ShallowMixin
+);
+
+ReactShallowRenderer.prototype.render = function(element) {
+  var transaction = ReactUpdates.ReactReconcileTransaction.getPooled();
+  this._render(element, transaction);
+  ReactUpdates.ReactReconcileTransaction.release(transaction);
+};
+
+ReactShallowRenderer.prototype._render = function(element, transaction) {
+  if (!this._instance) {
+    var rootID = ReactInstanceHandles.createReactRootID();
+    var instance = new ShallowComponentWrapper(new element.type(element.props));
+    instance.construct(element);
+
+    instance.mountComponent(rootID, transaction, 0);
+
+    this._instance = instance;
+  } else {
+    this._instance.receiveComponent(element, transaction);
+  }
+};
+
 /**
  * Exports:
  *

src/test/__tests__/ReactTestUtils-test.js

@@ -0,0 +1,113 @@
+/**
+ * Copyright 2013-2014, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @emails react-core
+ */
+
+"use strict";
+
+var React;
+var ReactTestUtils;
+
+var mocks;
+var warn;
+
+describe('ReactTestUtils', function() {
+
+  beforeEach(function() {
+    mocks = require('mocks');
+
+    React = require('React');
+    ReactTestUtils = require('ReactTestUtils');
+
+    warn = console.warn;
+    console.warn = mocks.getMockFunction();
+  });
+
+  afterEach(function() {
+    console.warn = warn;
+  });
+
+  it('should have shallow rendering', function() {
+    var SomeComponent = React.createClass({
+      render: function() {
+        return (
+          <div>
+            <span className="child1" />
+            <span className="child2" />
+          </div>
+        );
+      }
+    });
+
+    var shallowRenderer = ReactTestUtils.createRenderer();
+    shallowRenderer.render(<SomeComponent />);
+
+    var result = shallowRenderer.getRenderOutput();
+
+    expect(result.type).toBe('div');
+    expect(result.props.children).toEqual([
+      <span className="child1" />,
+      <span className="child2" />
+    ]);
+  });
+
+  it('lets you update shallowly rendered components', function() {
+    var SomeComponent = React.createClass({
+      getInitialState: function() {
+        return {clicked: false};
+      },
+
+      onClick: function() {
+        this.setState({clicked: true});
+      },
+
+      render: function() {
+        var className = this.state.clicked ? 'was-clicked' : '';
+
+        if (this.props.aNew === 'prop') {
+          return (
+            <a
+              href="#"
+              onClick={this.onClick}
+              className={className}>
+              Test link
+            </a>
+          );
+        } else {
+          return (
+            <div>
+              <span className="child1" />
+              <span className="child2" />
+            </div>
+          );
+        }
+      }
+    });
+
+    var shallowRenderer = ReactTestUtils.createRenderer();
+    shallowRenderer.render(<SomeComponent />);
+    var result = shallowRenderer.getRenderOutput();
+    expect(result.type).toBe('div');
+    expect(result.props.children).toEqual([
+      <span className="child1" />,
+      <span className="child2" />
+    ]);
+
+    shallowRenderer.render(<SomeComponent aNew="prop" />);
+    var updatedResult = shallowRenderer.getRenderOutput();
+    expect(updatedResult.type).toBe('a');
+
+    var mockEvent = {};
+    updatedResult.props.onClick(mockEvent);
+
+    var updatedResultCausedByClick = shallowRenderer.getRenderOutput();
+    expect(updatedResultCausedByClick.type).toBe('a');
+    expect(updatedResultCausedByClick.props.className).toBe('was-clicked');
+  });
+});