Only fire input value change events when the value changes (#5746)

* Only fire input value change events when the value changes

fixes #554, fixes #1471, fixes #2185 (still trying to figure out why)

* catch programmatic value changes

* move value tracking to seperate module

src/renderers/dom/client/__tests__/inputValueTracking-test.js

@@ -0,0 +1,165 @@
+/**
+ * Copyright 2013-present, 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 = require('React');
+var ReactTestUtils = require('ReactTestUtils');
+var inputValueTracking = require('inputValueTracking');
+
+describe('inputValueTracking', function() {
+  var input, checkbox, mockComponent;
+
+  beforeEach(function() {
+    input = document.createElement('input');
+    input.type = 'text';
+    checkbox = document.createElement('input');
+    checkbox.type = 'checkbox';
+    mockComponent = { _nativeNode: input, _wrapperState: {} };
+  });
+
+  it('should attach tracker to wrapper state', function() {
+    inputValueTracking.track(mockComponent);
+
+    expect(
+      mockComponent._wrapperState.hasOwnProperty('valueTracker')
+    ).toBe(true);
+  });
+
+  it('should define `value` on the instance node', function() {
+    inputValueTracking.track(mockComponent);
+
+    expect(
+      input.hasOwnProperty('value')
+    ).toBe(true);
+  });
+
+  it('should define `checked` on the instance node', function() {
+    mockComponent._nativeNode = checkbox;
+    inputValueTracking.track(mockComponent);
+
+    expect(checkbox.hasOwnProperty('checked')).toBe(true);
+  });
+
+  it('should initialize with the current value', function() {
+    input.value ='foo';
+
+    inputValueTracking.track(mockComponent);
+
+    var tracker = mockComponent._wrapperState.valueTracker;
+
+    expect(tracker.getValue()).toEqual('foo');
+  });
+
+  it('should initialize with the current `checked`', function() {
+    mockComponent._nativeNode = checkbox;
+    checkbox.checked = true;
+    inputValueTracking.track(mockComponent);
+
+    var tracker = mockComponent._wrapperState.valueTracker;
+
+    expect(tracker.getValue()).toEqual('true');
+  });
+
+  it('should track value changes', function() {
+    input.value ='foo';
+
+    inputValueTracking.track(mockComponent);
+
+    var tracker = mockComponent._wrapperState.valueTracker;
+
+    input.value ='bar';
+    expect(tracker.getValue()).toEqual('bar');
+  });
+
+  it('should tracked`checked` changes', function() {
+    mockComponent._nativeNode = checkbox;
+    checkbox.checked = true;
+    inputValueTracking.track(mockComponent);
+
+    var tracker = mockComponent._wrapperState.valueTracker;
+
+    checkbox.checked = false;
+    expect(tracker.getValue()).toEqual('false');
+  });
+
+  it('should update value manually', function() {
+    input.value ='foo';
+    inputValueTracking.track(mockComponent);
+
+    var tracker = mockComponent._wrapperState.valueTracker;
+
+    tracker.setValue('bar');
+    expect(tracker.getValue()).toEqual('bar');
+  });
+
+  it('should coerce value to a string', function() {
+    input.value ='foo';
+    inputValueTracking.track(mockComponent);
+
+    var tracker = mockComponent._wrapperState.valueTracker;
+
+    tracker.setValue(500);
+    expect(tracker.getValue()).toEqual('500');
+  });
+
+  it('should update value if it changed and return result', function() {
+    inputValueTracking.track(mockComponent);
+    input.value ='foo';
+
+    var tracker = mockComponent._wrapperState.valueTracker;
+
+    expect(
+      inputValueTracking.updateValueIfChanged(mockComponent)
+    ).toBe(false);
+
+    tracker.setValue('bar');
+
+    expect(
+      inputValueTracking.updateValueIfChanged(mockComponent)
+    ).toBe(true);
+
+    expect(tracker.getValue()).toEqual('foo');
+  });
+
+  it('should track value and return true when updating untracked instance', function() {
+    input.value ='foo';
+
+    expect(
+      inputValueTracking.updateValueIfChanged(mockComponent)
+    )
+    .toBe(true);
+
+    var tracker = mockComponent._wrapperState.valueTracker;
+    expect(tracker.getValue()).toEqual('foo');
+  });
+
+  it('should return tracker from node', function() {
+    var node = ReactTestUtils.renderIntoDocument(<input type="text" defaultValue="foo" />);
+    var tracker = inputValueTracking._getTrackerFromNode(node);
+    expect(tracker.getValue()).toEqual('foo');
+  });
+
+  it('should stop tracking', function() {
+    inputValueTracking.track(mockComponent);
+
+    expect(
+      mockComponent._wrapperState.hasOwnProperty('valueTracker')
+    ).toBe(true);
+
+    inputValueTracking.stopTracking(mockComponent);
+
+    expect(
+      mockComponent._wrapperState.hasOwnProperty('valueTracker')
+    ).toBe(false);
+
+    expect(input.hasOwnProperty('value')).toBe(false);
+  });
+});