title: How to clear the value entered in react-datetime?
body: <p>I am using react-datetime for our calendar control.Now the issue is
  that if the user entered an invalid date like 'djfdjfhjkhdf' then in
  this control nothing is there to validate.So I decided to write my own
  validation function and call that on blur event if the date is invalid
  then clear the text entered by the user.My code is like this:-</p>
  
  <pre><code>import DatePicker from 'react-datetime';
  
  focousOut(value) {
  if (!validateDate(value)) {
    this.setState({ startDate:  ''});
    this.setState({ selectedValue: '' });
   }
  }
  handleChange(date) {
   this.setState({ selectedValue: date });
   this.setState({ startDate: date });
  }
  
  &lt;Datetime
    timeFormat={false}
    value={this.state.selectedValue}
    defaultValue={this.state.startDate}
    onChange={this.handleChange}
    onBlur={this.focousOut}
    locale='en-US'
    dateFormat
    closeOnSelect
  /&gt;
  </code></pre>