JSFiddle - React, Tailwind, and code Playground

JavaScript

var d = new Date();
                var year = d.getFullYear();
                var month = d.getMonth();
                var day = d.getDate();
                var dtMax = new Date(year - 18, month, day,0,0,0);
                var converted = dtMax.toISOString('YYYY-MM-DD');
                alert(dtMax);