JSFiddle - React, Tailwind, and code Playground

JavaScript

function unixTime(unixtime) {
      var u = new Date(unixtime*1000);
        return u.getUTCFullYear() +
          '-' + ('0' + u.getUTCMonth()).slice(-2) +
          '-' + ('0' + u.getUTCDate()).slice(-2)
        //  ' ' + ('0' + u.getUTCHours()).slice(-2) +
      //    ':' + ('0' + u.getUTCMinutes()).slice(-2) +
        //  ':' + ('0' + u.getUTCSeconds()).slice(-2)
      }
      
      var test = unixTime(1638178329);
      
      console.log(test);