prefer-set-operation.md

Pattern: Missing use of character class set operation

Issue: -

Description

Regular expressions with the v flag have access to character class set operations (e.g. /[\s&&\p{ASCII}]/v, /[\w--\d]/v). These are more readable and performant than using lookarounds to achieve the same effect.

Examples

/* eslint regexp/prefer-set-operation: "error" */
/* ✓ GOOD */
var foo = /(?!\d)\w/  // requires the v flag
var foo = /(?!\d)\w/u // requires the v flag

/* ✗ BAD */
var foo = /(?!\d)\w/v
var foo = /(?!\s)[\w\P{ASCII}]/v