isDiscover

isDiscover :: a → Boolean

Reports whether the received value is a valid credit card number and is a Discover card

import isDiscover from 'deep-waters/credit-cards/isDiscover';

isDiscover(6011583945260254); // Discover → true

isDiscover(347190259623701); // American Express → false
isDiscover(4286124395547263); // VISA → false
isDiscover(38716394960899); // Diners Club → false
isDiscover(3528701379615495); // JCB → false
isDiscover('6011-5839-4526-0254'); // Credit card format → false
isDiscover("foo"); // → false
isDiscover(undefined); // → false

Please note, isDiscover assumes the receiving value is a number or a string without the usual dashes. It only evaluates the credit card number, not its format.