Support two-way binding for checkboxes in LinkedValueMixin via 'checkedLink' property

src/dom/components/LinkedValueUtils.js

@@ -27,7 +27,7 @@ var hasReadOnlyValue = {
   'radio': true
 };
 
-function _assertLink(input) {
+function _assertValueLink(input) {
   invariant(
     input.props.value == null && input.props.onChange == null,
     'Cannot provide a valueLink and a value or onChange event. If you want ' +
@@ -35,6 +35,15 @@ function _assertLink(input) {
   );
 }
 
+function _assertCheckedLink(input) {
+  invariant(
+    input.props.checked == null && input.props.onChange == null,
+    'Cannot provide a checkedLink and a checked property or onChange event. ' +
+    'If you want to use checked or onChange, you probably don\'t want to ' +
+    'use checkedLink'
+  );
+}
+
 /**
  * @param {SyntheticEvent} e change event to handle
  */
@@ -43,6 +52,14 @@ function _handleLinkedValueChange(e) {
   this.props.valueLink.requestChange(e.target.value);
 }
 
+/**
+  * @param {SyntheticEvent} e change event to handle
+  */
+function _handleLinkedCheckChange(e) {
+  /*jshint validthis:true */
+  this.props.checkedLink.requestChange(e.target.checked === 'true');
+}
+
 /**
  * Provide a linked `value` attribute for controlled forms. You should not use
  * this outside of the ReactDOM controlled form components.
@@ -65,6 +82,21 @@ var LinkedValueUtils = {
             );
           }
         }
+      },
+      checked: function(props, propName, componentName) {
+        if (__DEV__) {
+          if (props[propName] &&
+              !props.onChange &&
+              !props.readOnly &&
+              !props.disabled) {
+            console.warn(
+              'You provided a `checked` prop to a form field without an ' +
+              '`onChange` handler. This will render a read-only field. If ' +
+              'the field should be mutable use `defaultChecked`. Otherwise, ' +
+              'set either `onChange` or `readOnly`.'
+            );
+          }
+        }
       }
     }
   },
@@ -75,20 +107,36 @@ var LinkedValueUtils = {
    */
   getValue: function(input) {
     if (input.props.valueLink) {
-      _assertLink(input);
+      _assertValueLink(input);
       return input.props.valueLink.value;
     }
     return input.props.value;
   },
 
+  /**
+   * @param {ReactComponent} input Form component
+   * @return {*} current checked status of the input either from checked prop
+   *             or link.
+   */
+  getChecked: function(input) {
+    if (input.props.checkedLink) {
+      _assertCheckedLink(input);
+      return input.props.checkedLink.value;
+    }
+    return input.props.checked;
+  },
+
   /**
    * @param {ReactComponent} input Form component
    * @return {function} change callback either from onChange prop or link.
    */
   getOnChange: function(input) {
     if (input.props.valueLink) {
-      _assertLink(input);
+      _assertValueLink(input);
       return _handleLinkedValueChange;
+    } else if (input.props.checkedLink) {
+      _assertCheckedLink(input);
+      return _handleLinkedCheckChange;
     }
     return input.props.onChange;
   }

src/dom/components/ReactDOMInput.js

@@ -73,12 +73,13 @@ var ReactDOMInput = ReactCompositeComponent.createClass({
 
     props.defaultChecked = null;
     props.defaultValue = null;
-    props.checked =
-      this.props.checked != null ? this.props.checked : this.state.checked;
 
     var value = LinkedValueUtils.getValue(this);
     props.value = value != null ? value : this.state.value;
 
+    var checked = LinkedValueUtils.getChecked(this);
+    props.checked = checked != null ? checked : this.state.checked;
+
     props.onChange = this._handleChange;
 
     return input(props, this.props.children);

src/dom/components/__tests__/ReactDOMInput-test.js

@@ -252,4 +252,77 @@ describe('ReactDOMInput', function() {
     expect(React.renderComponent.bind(React, instance, node)).toThrow();
 
   });
+
+  it('should support checkedLink', function() {
+    var container = document.createElement('div');
+    var link = new ReactLink(true, mocks.getMockFunction());
+    var instance = <input type="checked" checkedLink={link} />;
+
+    React.renderComponent(instance, container);
+
+    expect(instance.getDOMNode().checked).toBe(true);
+    expect(link.value).toBe(true);
+    expect(link.requestChange.mock.calls.length).toBe(0);
+
+    instance.getDOMNode().checked = false;
+    ReactTestUtils.Simulate.input(instance.getDOMNode());
+
+    expect(link.requestChange.mock.calls.length).toBe(1);
+    expect(link.requestChange.mock.calls[0][0]).toEqual(false);
+  });
+
+  it('should warn with checked and no onChange handler', function() {
+    var oldWarn = console.warn;
+    try {
+      console.warn = mocks.getMockFunction();
+
+      var node = document.createElement('div');
+      var link = new ReactLink(true, mocks.getMockFunction());
+      React.renderComponent(<input type="checkbox" checkedLink={link} />, node);
+      expect(console.warn.mock.calls.length).toBe(0);
+
+      React.renderComponent(
+        <input type="checkbox" checked="false" onChange={mocks.getMockFunction()} />,
+        node
+      );
+      expect(console.warn.mock.calls.length).toBe(0);
+
+      React.renderComponent(
+        <input type="checkbox" checked="false" readOnly={true} />,
+        node
+      );
+      expect(console.warn.mock.calls.length).toBe(0);
+
+      React.renderComponent(<input type="checkbox" checked="false" />, node);
+      expect(console.warn.mock.calls.length).toBe(1);
+
+      React.renderComponent(
+        <input type="checkbox" checked="false" readOnly={false} />,
+        node
+      );
+      expect(console.warn.mock.calls.length).toBe(2);
+    } finally {
+      console.warn = oldWarn;
+    }
+  });
+
+  it('should throw if both checked and checkedLink are provided', function() {
+    // Silences console.error messages
+    // ReactErrorUtils.guard is applied to all methods of a React component
+    // and calls console.error in __DEV__ (true for test environment)
+    spyOn(console, 'error');
+
+    var node = document.createElement('div');
+    var link = new ReactLink(true, mocks.getMockFunction());
+    var instance = <input type="checkbox" checkedLink={link} />;
+
+    expect(React.renderComponent.bind(React, instance, node)).not.toThrow();
+
+    instance = <input type="checkbox" checkedLink={link} checked="false" />;
+    expect(React.renderComponent.bind(React, instance, node)).toThrow();
+
+    instance = <input type="checkbox" checkedLink={link} onChange={emptyFunction} />;
+    expect(React.renderComponent.bind(React, instance, node)).toThrow();
+
+  });
 });