It doesn’t have a `@flow` annotation. We should start Flow-ifying it to avoid bugs like https://github.com/facebook/react/pull/11173.

@iamdustan Wanna take it?
defaultValue: undefined,
          value: props.value != null ? props.value : props.defaultValue,
          checked: props.checked != null ? props.checked : props.defaultChecked,
        },
      );
    } else if (tag === 'textarea') {
      if (__DEV__) {
        ReactControlledValuePropTypes.checkPropTypes(
          'textarea',
          props,
          getStackAddendum,
        );
        if (
          props.value !== undefined &&
          props.defaultValue !== undefined &&
          !didWarnDefaultTextareaValue
        ) {
          warning(
            false,
            'Textarea elements must be either controlled or uncontrolled ' +
              '(specify either the value prop, or the defaultValue prop, but not ' +
              'both). Decide between using a controlled or uncontrolled textarea ' +
              'and remove one of these props. More info: ' +
              'https://fb.me/react-controlled-components',
          );
          didWarnDefaultTextareaValue = true;
        }
      }
      var initialValue = props.value;
      if (initialValue == null) {