| /** |
| * @fileoverview Rule to flag the use of empty character classes in regular expressions |
| * @author Ian Christian Myers |
| */ |
| |
| "use strict"; |
| |
| //------------------------------------------------------------------------------ |
| // Helpers |
| //------------------------------------------------------------------------------ |
| |
| /* |
| * plain-English description of the following regexp: |
| * 0. `^` fix the match at the beginning of the string |
| * 1. `\/`: the `/` that begins the regexp |
| * 2. `([^\\[]|\\.|\[([^\\\]]|\\.)+\])*`: regexp contents; 0 or more of the following |
| * 2.0. `[^\\[]`: any character that's not a `\` or a `[` (anything but escape sequences and character classes) |
| * 2.1. `\\.`: an escape sequence |
| * 2.2. `\[([^\\\]]|\\.)+\]`: a character class that isn't empty |
| * 3. `\/` the `/` that ends the regexp |
| * 4. `[gimuy]*`: optional regexp flags |
| * 5. `$`: fix the match at the end of the string |
| */ |
| const regex = /^\/([^\\[]|\\.|\[([^\\\]]|\\.)+\])*\/[gimuys]*$/u; |
| |
| //------------------------------------------------------------------------------ |
| // Rule Definition |
| //------------------------------------------------------------------------------ |
| |
| module.exports = { |
| meta: { |
| type: "problem", |
| |
| docs: { |
| description: "disallow empty character classes in regular expressions", |
| category: "Possible Errors", |
| recommended: true, |
| url: "https://eslint.org/docs/rules/no-empty-character-class" |
| }, |
| |
| schema: [], |
| |
| messages: { |
| unexpected: "Empty class." |
| } |
| }, |
| |
| create(context) { |
| const sourceCode = context.getSourceCode(); |
| |
| return { |
| |
| Literal(node) { |
| const token = sourceCode.getFirstToken(node); |
| |
| if (token.type === "RegularExpression" && !regex.test(token.value)) { |
| context.report({ node, messageId: "unexpected" }); |
| } |
| } |
| |
| }; |
| |
| } |
| }; |