JSFiddle - React, Tailwind, and code Playground

JavaScript

function date() {
    let str = '';

    const currentTime = new Date();
    let year = currentTime.getFullYear().toString();
    let month = currentTime.getMonth().toString();
    let day = currentTime.getDate().toString();

    let hours = currentTime.getHours().toString();
    let minutes = currentTime.getMinutes().toString();
    let seconds = currentTime.getSeconds().toString();
    if ( month < 10) {
        month = '0' + month;
    }
    if ( minutes < 10) {
        minutes = '0' + minutes;
    }
    if (seconds < 10) {
        seconds = '0' + seconds;
    }
    str += year + '-' + month + '-' + day + ' ' + hours + ':' + minutes + ':' + seconds + ' ';

    alert(str);
}

date();