eslint/docs/rules/prefer-named-capture-group.md

   1 # Suggest using named capture group in regular expression (prefer-named-capture-group)
   2
   3 With the landing of ECMAScript 2018, named capture groups can be used in regular expressions, which can improve their readability.
   4
   5 ```js
   6 const regex = /(?<year>[0-9]{4})/;
   7 ```
   8
   9 ## Rule Details
  10
  11 This rule is aimed at using named capture groups instead of numbered capture groups in regular expressions.
  12
  13 Examples of **incorrect** code for this rule:
  14
  15 ```js
  16 /*eslint prefer-named-capture-group: "error"*/
  17
  18 const foo = /(ba[rz])/;
  19 const bar = new RegExp('(ba[rz])');
  20 const baz = RegExp('(ba[rz])');
  21
  22 foo.exec('bar')[1]; // Retrieve the group result.
  23 ```
  24
  25 Examples of **correct** code for this rule:
  26
  27 ```js
  28 /*eslint prefer-named-capture-group: "error"*/
  29
  30 const foo = /(?<id>ba[rz])/;
  31 const bar = new RegExp('(?<id>ba[rz])');
  32 const baz = RegExp('(?<id>ba[rz])');
  33
  34 foo.exec('bar').groups.id; // Retrieve the group result.
  35 ```
  36
  37 ## When Not To Use It
  38
  39 If you are targeting ECMAScript 2017 and/or older environments, you can disable this rule, because this ECMAScript feature is only supported in ECMAScript 2018 and/or newer environments.
  40
  41 ## Related Rules
  42
  43 * [no-invalid-regexp](./no-invalid-regexp.md)