Question 1

How do I prevent ReDOS attacks with compose-regexp?

Accepted Answer

Use the atomic() function to wrap regex parts prone to backtracking; it creates atomic groups that eliminate exponential backtracking, making patterns safe from ReDOS vulnerabilities as demonstrated in the fixing ReDOS example.

Question 2

compose-regexp vs writing regex literals: which is better?

Accepted Answer

compose-regexp is better for complex, maintainable regex patterns with ReDOS protection and composability, while regex literals are simpler for one-off tasks without library overhead.

Question 3

How to use lookbehind assertions with compose-regexp?

Accepted Answer

Use the lookBehind() and notBehind() functions; for atomic matching in lookbehind, wrap arguments in a function to handle backward context, as explained in the atomic matching section.

Question 4

Does compose-regexp support Unicode properties?

Accepted Answer

Yes, it supports Unicode properties via the u flag and character set operations, allowing intersections like /\p{Lowercase}/u and /\p{Script=Greek}/u for precise matching, shown in the character set examples.

Question 5

What browsers are supported by compose-regexp?

Accepted Answer

It requires ES5 with polyfills like Object.assign, but full feature support depends on the engine's RegExp capabilities; older browsers may lack Unicode or lookbehind support, limiting functionality.

Question 6

How to handle back references in nested regex compositions?

Accepted Answer

Use the ref() function with an optional depth parameter to reference captures from higher levels, ensuring correct numbering as detailed in the back references section for complex compositions.

compose-regexp.js

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