ppc_amnet/amnet-shared/src/card.ts

export const CARD_ID_REGEX = /^(?:[0-9]{4} ?){5}$/i;

export function generateCardNumber(): string {
    let cardId = '';

    while (true) {
        // don't start with a 3
        const firstDigit = Math.floor(Math.random() * 10);

        if (firstDigit !== 3) {
            cardId = firstDigit.toString();
            break;
        }
    }

    for (let i = 0; i < 19; i++) {
        cardId += Math.floor(Math.random() * 10).toString();
    }

    return cardId;
}

/**
 * Validates the provided card id by known parameters
 * @param id The card id to validate
 */
export function validateCardId(id: string): boolean {
    return id[0] !== '3' && CARD_ID_REGEX.test(id);
}