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Commit | Line | Data |
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eb39fafa DC |
1 | /** |
2 | * @fileoverview Rule to flag the use of empty character classes in regular expressions | |
3 | * @author Ian Christian Myers | |
4 | */ | |
5 | ||
6 | "use strict"; | |
7 | ||
8 | //------------------------------------------------------------------------------ | |
9 | // Helpers | |
10 | //------------------------------------------------------------------------------ | |
11 | ||
12 | /* | |
13 | * plain-English description of the following regexp: | |
14 | * 0. `^` fix the match at the beginning of the string | |
609c276f TL |
15 | * 1. `([^\\[]|\\.|\[([^\\\]]|\\.)+\])*`: regexp contents; 0 or more of the following |
16 | * 1.0. `[^\\[]`: any character that's not a `\` or a `[` (anything but escape sequences and character classes) | |
17 | * 1.1. `\\.`: an escape sequence | |
18 | * 1.2. `\[([^\\\]]|\\.)+\]`: a character class that isn't empty | |
19 | * 2. `$`: fix the match at the end of the string | |
eb39fafa | 20 | */ |
609c276f | 21 | const regex = /^([^\\[]|\\.|\[([^\\\]]|\\.)+\])*$/u; |
eb39fafa DC |
22 | |
23 | //------------------------------------------------------------------------------ | |
24 | // Rule Definition | |
25 | //------------------------------------------------------------------------------ | |
26 | ||
34eeec05 | 27 | /** @type {import('../shared/types').Rule} */ |
eb39fafa DC |
28 | module.exports = { |
29 | meta: { | |
30 | type: "problem", | |
31 | ||
32 | docs: { | |
33 | description: "disallow empty character classes in regular expressions", | |
eb39fafa DC |
34 | recommended: true, |
35 | url: "https://eslint.org/docs/rules/no-empty-character-class" | |
36 | }, | |
37 | ||
38 | schema: [], | |
39 | ||
40 | messages: { | |
41 | unexpected: "Empty class." | |
42 | } | |
43 | }, | |
44 | ||
45 | create(context) { | |
eb39fafa | 46 | return { |
609c276f TL |
47 | "Literal[regex]"(node) { |
48 | if (!regex.test(node.regex.pattern)) { | |
eb39fafa DC |
49 | context.report({ node, messageId: "unexpected" }); |
50 | } | |
51 | } | |
eb39fafa DC |
52 | }; |
53 | ||
54 | } | |
55 | }; |