title: How can i make my placeholder show on datepicker input?
body: <p>I have a <code>react-datepicker</code> component inside my form and i am trying to put a placeholder which says "please select a date" but datepicker only shows the date.I did research and some people say placeholder shows only if <code>selected={...}</code>  is false but i don't know how to make my <code>selected={}</code> false on default and show on toggle.</p>
  
  <p>I tried to use react-datepicker's code,it is <code>placeholderText=""</code> but i couldn't implemented it</p>
  
  <p>this is my state in my form;</p>
  
  <pre><code>bookTime: {
            data: new Date(),
            name: "bookTime",
            category: "text",
            everFocused: false,
            isValid: true,         
            extra : {
              label:"Randevu Tarihi*",
              help: "Geçersiz Alan!"
            }
         },
  </code></pre>
  
  <p>this is my datepicker component;</p>
  
  <pre><code>&lt;DatePicker className="turkish"
                    locale={tr}
                    placeholderText="Please select a date"
                    onChange={this.handleChangeDatePicker}
                    onChangeRaw={this.handleDateChangeRaw}
                    selected={bookTime.data }
  
                    showTimeSelect
                    minTime={setHours(setMinutes(new Date(), 0), 7)}
                    maxTime={setHours(setMinutes(new Date(), 0), 22)}
                    minDate={subDays(new Date(), 0)}
  
                    timeFormat="HH:mm"
                    timeIntervals={60}
                    dateFormat="HH:mm,d MMMM yyyy"
                    timeCaption="Saat"
  
                  /&gt;
  </code></pre>