JSFiddle - React, Tailwind, and code Playground

JavaScript

function two_weeks_ago(date_object) {
    var two_weeks = 1209600000; // two weeks in milliseconds

    var total = date_object.getTime() - two_weeks;
    var date  = new Date(total);

    return date.getFullYear() +'/'+ (date.getMonth() + 1) +'/'+ date.getDate();
}

$('body').append( two_weeks_ago(new Date()) + '<br>');