no-octal-escape.md

no-octal-escape

Disallow octal escapes outside of character classes.

configuration in plugin:clean-regex/recommended: "error"

Source file
Test file

Description

Octal escapes can easily be confused with backreferences because the same character sequence (e.g. \3) can either be used to escape a character or to reference a capturing group depending on the number of capturing groups in the pattern.

This can be a problem when refactoring regular expressions because an octal escape can become a backreference or wise versa.

To prevent this issue, this rule disallows all octal escapes outside of character classes.

Examples

Examples of valid code for this rule:

/\x10\0/
/(a)\1/
/[\1]/   // allowed because backreferences cannot be in character classes

Examples of invalid code for this rule:

/(a)\2/ // warns about `\2`