React 0.14.7: `<option value="">empty</option>` emits empty string on change
http://jsbin.com/pisita/10/edit?html,js,console,output
React 15.0.0-rc.1`<option value="">empty</option>` emits string with value "empty" on change
http://jsbin.com/bemaze/12/edit?html,js,console,output
This is because React 15.0.0-rc.1 cuts off `value=""` from option tag

if (typeof obj === 'object') {
    if (Array.isArray(obj)) {
      return '[' + obj.map(friendlyStringify).join(', ') + ']';
    } else {
      var pairs = [];
      for (var key in obj) {
        if (Object.prototype.hasOwnProperty.call(obj, key)) {
          var keyEscaped = /^[a-z$_][\w$_]*$/i.test(key) ?
            key :
            JSON.stringify(key);
          pairs.push(keyEscaped + ': ' + friendlyStringify(obj[key]));
        }
      }
      return '{' + pairs.join(', ') + '}';
    }
  } else if (typeof obj === 'string') {
    return JSON.stringify(obj);
  } else if (typeof obj === 'function') {
    return '[function object]';
  }
  
  
  return String(obj);
}
var styleMutationWarning = {};
function checkAndWarnForMutatedStyle(style1, style2, component) {
  if (style1 == null || style2 == null) {
    return;
  }
  if (shallowEqual(style1, style2)) {