Npm Email Validation Libraries

When Are Email Validation Libraries Useful

Email validation libraries are crucial tools that are widely used in various scenarios and services such as sign-up forms, contact forms, and anywhere else where email input is required. They prove to be especially useful in:

• Input validation: Almost every application that requires the user's email needs to ensure that it is valid before any further action. This could be for sending newsletters, invoices, receipts, etc.
• Data Cleansing: If you have a list of users' data and are unsure of the validity of their emails, validation libraries can be beneficial to clean it up.
• Avoiding fake sign-ups: Spambots and users often input fake emails. If not validated, these entries could lead to resource wastage.

Functionalities that Email Validation Libraries Usually Have

Most email validation libraries tend to offer a set of comprehensive functionalities to ensure a foolproof validation process:

• Syntax check: This includes checking if the email is in a correct format according to the RFC 5322.
• Domain check: Libraries validate the domain of the email address is actually registered.
• SMTP check: Some validation libraries also provide SMTP (Simple Mail Transfer Protocol) verification. This involves confirming whether the server on the provided domain is configured to receive email.
• Disposable email address check: Certain libraries can detect disposable (or throwaway) email addresses to help avoid spam.
• Checking against a known list of common misspellings: Many libraries maintain a list of common misspelled email domains, like "gnail.com" instead of "gmail.com".

Gotchas/Pitfalls to Look Out For

Despite their usefulness, there are a few gotchas and pitfalls to consider when using email validation libraries:

• Not all libraries offer SMTP Check: Not every email validation library does an SMTP check. A library without this feature could report a well-formatted, but non-existent email as valid.
• Library Maintenance: Libraries that haven't been updated recently may not recognize newly-created domains as valid. Always check the maintenance status of a library before using it.
• Privacy Issues: During SMTP check, some libraries send an email or 'ping' the email server which can be interpreted as a privacy violation. Be careful and make sure to choose a library that respects privacy.
• Common misspelling check: This feature is handy, but it can also flag real, albeit unusual, email domains as invalid. This can lead to false positives if not carefully managed.

When considering the mentioned functionalities and potential pitfalls, always make sure to thoroughly survey the options available in the npm package manager and choose a library that suits the specific needs of your application.