regexp/noUnusedCapturingGroup

Flags regex literals that contain capturing groups but no corresponding backreferences. This rule is heuristic and may produce false positives.

• Category: Core (optional)
• Default: off

Config:

rules: { noUnusedCapturingGroup: 'warn' } // 'off' | 'warn' | 'error'

Example:

const r = /(\d{4})-(\d{2})-(\d{2})/
// no backreference usage detected

Rationale: unused capturing groups can be converted to non-capturing (?:...) for performance/readability.

Suggested fix

Replace unused () with (?:...):

const r = /\d{4}-\d{2}-\d{2}/

Best practices

• Name only the groups you need to reference; prefer non-capturing groups otherwise
• Consider ?: for grouping without capture to reduce backreference complexity
• Keep complex regexes commented or broken into smaller parts for maintainability