JSFiddle - React, Tailwind, and code Playground

HTML

<input id="datePicker" type="date" />
<input type="button" id="test" value="test"/>

JavaScript

$(document).ready( function() {
    var now = new Date();
 
    var day = ("0" + now.getDate()).slice(-2);
    var month = ("0" + (now.getMonth() + 1)).slice(-2);

    var today = now.getFullYear()+"-"+(month)+"-"+(day) ;


   $('#datePicker').val(today);
    
    $('#test').click(function(){
        
        testClicked();
        
    });
});
function testClicked()
{
    
console.log(    $('#datePicker').val());    
}