Validating different string types with RegEx in JavaScript.

credit_card_validation.js

// following regex lets you validate credit cards and their types (including Visa, Mastercard, American Express and Discover cards)

^(?:4[0-9]{12}(?:[0-9]{3})?         // Visa
| 5[1-5][0-9]{14}                   // Mastercard
| 3[47][0-9]{13}                    // American Express
| 6(?:011|5[0-9]{2})[0-9]{12}       // Discover
)$

date_validation.js

// these regex patterns can be used to check valid date format or to check much complex information for different months and leap years

// option 1 (simply checks for YYYY-MM-DD format)
^\d{4}-\d{2}-\d{2}$

// option 2 (advanced solution, this regex pattern validates dates in the format of dd/mm/yyyy, including leap years and different month lengths)
/^(?:(?:31(/)(?:0?[13578]|1[02]))\1|(?:(?:29|30)(/)(?:0?[1,3-9]|1[0-2])\2))(?:(?:1[6-9]|[2-9]\d)?\d{2})$|^(?:29(/)0?2\3(?:(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00))))$|^(?:0?[1-9]|1\d|2[0-8])(/)(?:(?:0?[1-9])|(?:1[0-2]))\4(?:(?:1[6-9]|[2-9]\d)?\d{2})$/

email_validation.js

// these regex patterns validate an email address and check if it is in the correct format

// option 1
^[^\s@]+@[^\s@]+\.[^\s@]+$

// option 2
/^[\w-.]+@([\w-]+.)+[\w-]{2,4}$/

hex_color_code_validation.js

// this regex pattern lets you check for a valid hex color code

^#([A-Fa-f0-9]{6}|[A-Fa-f0-9]{3})$

ip_address_validation.js

// following regex validates IP addresses

^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$

password_validation.js

// these regex patterns ensure that password has at least one uppercase letter, one lowercase letter, one digit, one special character, and atleast 8 characters long

// option 1
^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*?&])[A-Za-z\d@$!%*?&]{8,}$

// option 2
/^(?=.[a-z])(?=.[A-Z])(?=.\d)(?=.[@$!%?&])[A-Za-z\d@$!%?&]{8,}$/

phone_number_validation.js

// these regex patterns can be used to check valid phone numbers either for US or any specific country or the advanced solution for global numbers with/without country codes

// option 1 (checks for US format only)
^\d{3}-\d{3}-\d{4}$

// option 2 (advanced solution, this regex pattern validates phone numbers and allows for various formats including with or without country code and with or without separators like hyphens, dots, or spaces)
/^[+]?[(]?[0-9]{3}[)]?[-\s.]?[0-9]{3}[-\s.]?[0-9]{4,6}$/

url_validation.js

// this regex pattern checks if a string is a valid URL

// option 1
^(https?:\/\/)?([\da-z\.-]+)\.([a-z\.]{2,6})([\/\w\.-]*)*\/?$

// option 2
/^(http(s)?://)?[a-zA-Z0-9-.]+.[a-zA-Z]{2,}(:[0-9]{1,5})?(/\S*)?$/