Email fixed validation with regular expression in Javascript

Question

I am working on email validations using regular expressions, where I need some fixed email values to validate before proceeding

Here is a clear requirement

User can only have up to 50 character before the Octets (@) and a maximum of 25 characters after the Octets, with a total of 80 characters

I used normal regex to validate email like

let reg = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/;

And now for the above requirement I am trying to create an expression like

let reg = /^\w+([\.-]?(\w{2,50})+)*@(\w{2,25})+([\.-]?\w+)*(\.\w{2,3})+$/;

But it's taking only starting character(not accepting lower than two) and not the last number of requirement, So any help would be appreciated.

The fourth bird · Accepted Answer · 2020-09-21 20:48:46Z

1

If you want to match 1-50 word chars before the @ (so no . or -) and 1-25 word chars after the @ (also no . or -) and a total of no more than 80 chars:

^(?!.{81})(?:\w+[.-])*\w{1,50}@\w{1,25}(?:[.-]\w+)*\.\w{2,3}$

Explanation

^ Start of string
(?!.{81}) Negative lookahead, assert that from the current position there are not 81 chars directly to the right
(?:\w+[.-])* Repeat 0+ times 1+ word chars and either a . or -
\w{1,50} Match 1-50 word chars
@ Match literally
\w{1,25} Match 1-25 word chars
(?:[.-]\w+)* Repeat 0+ times matching either a . or - and 1+ word chars
\.\w{2,3} Match a . and 2-3 word chars
$ End of string

Regex demo

answered Sep 21, 2020 at 20:48

The fourth bird

165k16 gold badges61 silver badges75 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Konstantin Mezentsev Over a year ago

a little bit optimized your solution ^(?!.{81})[\w.-]{1,50}@[\w.-]{1,25}\.[a-z]{2,24}$ check online here according to this information, last part of domain name is currently 24 characters max

Kirankumar Dafda Over a year ago

Thank you so much for this quick response.

Collectives™ on Stack Overflow

Email fixed validation with regular expression in Javascript

1 Answer 1

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related