55 lines
1.6 KiB
JavaScript
55 lines
1.6 KiB
JavaScript
/**
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* @fileoverview Rule to flag the use of empty character classes in regular expressions
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* @author Ian Christian Myers
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*/
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"use strict";
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//------------------------------------------------------------------------------
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// Helpers
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//------------------------------------------------------------------------------
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/*
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* plain-English description of the following regexp:
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* 0. `^` fix the match at the beginning of the string
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* 1. `([^\\[]|\\.|\[([^\\\]]|\\.)+\])*`: regexp contents; 0 or more of the following
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* 1.0. `[^\\[]`: any character that's not a `\` or a `[` (anything but escape sequences and character classes)
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* 1.1. `\\.`: an escape sequence
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* 1.2. `\[([^\\\]]|\\.)+\]`: a character class that isn't empty
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* 2. `$`: fix the match at the end of the string
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*/
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const regex = /^([^\\[]|\\.|\[([^\\\]]|\\.)+\])*$/u;
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//------------------------------------------------------------------------------
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// Rule Definition
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//------------------------------------------------------------------------------
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/** @type {import('../shared/types').Rule} */
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module.exports = {
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meta: {
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type: "problem",
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docs: {
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description: "disallow empty character classes in regular expressions",
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recommended: true,
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url: "https://eslint.org/docs/rules/no-empty-character-class"
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},
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schema: [],
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messages: {
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unexpected: "Empty class."
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}
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},
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create(context) {
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return {
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"Literal[regex]"(node) {
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if (!regex.test(node.regex.pattern)) {
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context.report({ node, messageId: "unexpected" });
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}
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}
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};
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}
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};
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