JSFiddle - React, Tailwind, and code Playground

HTML

<input type="date" id="cal">

JavaScript

function openPicker(inputDateElem) {
    var ev = document.createEvent('KeyboardEvent');
    ev.initKeyboardEvent('keydown', true, true, document.defaultView, 'F4', 0);
    inputDateElem.dispatchEvent(ev);
}

var cal = document.querySelector('#cal');
cal.focus();
openPicker(cal);