Get formatted date in JS

// Attaching a new function  toShortFormat() to any instance of Date() class

Date.prototype.toShortFormat = function() {

    const months = ["Jan","Feb","Mar", "Apr","May","Jun", "Jul","Aug","Sep", "Oct","Nov","Dec"];
    const day = this.getDate();
    const monthIndex = this.getMonth();
    const year = this.getFullYear();
    
    return "" + day + "-" + months[monthIndex] + "-" + year;
}

// Now any Date object can be declared 
const today = new Date();

// and it can represent itself in the custom format defined above.
console.log(today.toShortFormat()); // current date