javascript regularer expression - how to simplify

Question

I am reading a javascript file which has few issues and I come across with a RegEx which looks like

/^(a|b|c|d|e|f|g|h|i|j|k|l|m|n|o|p|q|r|s|t|u|v|w|x|y|z){3}\d{3}|(a|b|c|d|e|f|g|h|i|j|k|l|m|n|o|p|q|r|s|t|u|v|w|x|y|z){3}(a|b|c|d|e|f|g|h|i|j|k|l|m|n|o|p|q|r|s|t|u|v|w|x|y|z){0,1}$/;

Firstly what it actually matches and how can I simplify it

Edit : Replace the alphabet part by [a-z] ;) `/^[a-z]{3}\d{3}|[a-z]{3}[a-z]{0,1}$/; ` — kaldoran, Apr 19 '17 at 09:56
... uhm, regex has character classes. for example `[a-z]{3}` to get 3 a to z characters. Those pipes are more used to seperate words. — LukStorms, Apr 19 '17 at 09:59

Cerbrus · Accepted Answer · 2017-04-19T10:00:01.830

0

That's functionally similar to:

/^([a-z]){3}\d{3}|([a-z]){3}([a-z]){0,1}$/;

This basically captures:

From the start of the string
3 characters in the a-z range followed by 3 digits, or
3 characters in the a-z range followed by 0 or 1 character in the a-z range.

edited Apr 19 '17 at 10:00

answered Apr 19 '17 at 09:57

Cerbrus

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I don't think you need the `()` anymore since they where is in order to apply the `|` – kaldoran Apr 19 '17 at 09:58
@kaldoran: Depends on what they were using it for (e.g., were they use the capture group). If it had been a non-capturing group `(?:a|b|...)`, it would definitely be unnecessary. – T.J. Crowder Apr 19 '17 at 09:59
@kaldoran: If they were being used as capture grops, you need'm. – Cerbrus Apr 19 '17 at 10:06

javascript regularer expression - how to simplify

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