Check comma separated email address is valid

The following Google Apps Script is designed to loop through a Google Sheet cell of email addresses that have been separated by a comma and space. It then uses a regular expression (regex) to confirm the email address meets the correct formatting criteria.

This code was developed as a way of implementing additional checks when asking users to be precise in how exactly they enter multiple email addresses. So if they were to forget the space for instance it could alert them, before the rest of the code risked failing as whatever task it was designed to do.

Regular expression to check the format of an email address

Regex breakdown

• ^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$
• ^  matches the beginning of the string.
• [a-zA-Z0-9._%+-]  match any character in this set e.g. from "a" to "z" and any "." or "_"
• +  match one or more of the preceding token.
• @  match a "@" character.
• [a-zA-Z0-9.-]  match any character in this set e.g. from "a" to "z" and any "." or "-"
• \.  escaped character to match a "."
• [a-zA-Z]  match any character in this set e.g. from "a" to "z"
• {2,}  match two or more of the preceding token.
• $  matches the end of the string.

Therefore something like "example1@gmail.com" will be accepted but "example2@gmailcom" will not.

Download

Check comma separated email address is valid download (please use 'File' > 'Make a copy' for your own version).