JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" id="js-cardnumber" />

JavaScript

$(function() {
    var $cardNumber = $('#js-cardnumber');

    var ccMap = {};

    ccMap.cards = {
        'amex': '^3[47][0-9]{13}$',
        'discover': '^6(?:011|5[0-9]{2})[0-9]{12}$',
        'mastercard': '^5[1-5][0-9]{14}$',
        'visa': '^4[0-9]{12}(?:[0-9]{3})?$'
    };


    $cardNumber.keydown(function() {
        for (var cardType in ccMap.cards) {
            if (ccMap.cards.hasOwnProperty(cardType)) {
                var regex = ccMap.cards[cardType];
               if ( $(this).val().match(regex) )  {
                    console.log(cardType);
                    return;
                }
            }
        }
    });
});