Regex: Possible to simplify this?

Question

I have this JavaScript Regex: /(\.abc$|^abc$|abc\.def$)/i. I feel like this is extremely redundant and it can be simplified. Here's what I'm trying to accomplish:
- It needs to match .abc only at the end or only abc or only abc.def

Edit: I realized I could place $ at the end of the parenthesis and it could become /(\.abc|^abc|abc\.def)$/i. However, this still seems redundant

Huh, figured that there could be a way to use `abc` once since they all contain that. — John Boyer, Apr 13 '18 at 00:08
According to your own regex and rules `^abc(?:\.def)?$|\.abc$` — revo, Apr 13 '18 at 00:10
An alternative: `(?:\.|^)?abc(?:\.def)?$`. However your original regex is more efficient than according to regex101. — builder-7000, Apr 13 '18 at 00:38
The `/(\.abc|^abc|abc\.def)$/i` is all you can do. Of course, you may [use a variable for a block](). But it is already a dupe then. See [this post](https://stackoverflow.com/questions/494035/how-do-you-use-a-variable-in-a-regular-expression). — Wiktor Stribiżew, Apr 13 '18 at 10:24

score 0 · Answer 1 · answered Apr 13 '18 at 23:17

0

You can only combine two of the options at a time because of the fork implied by .abc.def not matching at the end.

SO each case combines two and adds the remaining option:

(^abc(\.def)?|\.abc)$

((^|\.)abc|^abc\.def)$

answered Apr 13 '18 at 23:17

NetMage

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Regex: Possible to simplify this?

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