eslint/lib/rules/no-control-regex.js

   1 /**
   2  * @fileoverview Rule to forbid control characters from regular expressions.
   3  * @author Nicholas C. Zakas
   4  */
   5
   6 "use strict";
   7
   8 const RegExpValidator = require("regexpp").RegExpValidator;
   9 const collector = new (class {
  10     constructor() {
  11         this._source = "";
  12         this._controlChars = [];
  13         this._validator = new RegExpValidator(this);
  14     }
  15
  16     onPatternEnter() {
  17         this._controlChars = [];
  18     }
  19
  20     onCharacter(start, end, cp) {
  21         if (cp >= 0x00 &&
  22             cp <= 0x1F &&
  23             (
  24                 this._source.codePointAt(start) === cp ||
  25                 this._source.slice(start, end).startsWith("\\x") ||
  26                 this._source.slice(start, end).startsWith("\\u")
  27             )
  28         ) {
  29             this._controlChars.push(`\\x${`0${cp.toString(16)}`.slice(-2)}`);
  30         }
  31     }
  32
  33     collectControlChars(regexpStr) {
  34         try {
  35             this._source = regexpStr;
  36             this._validator.validatePattern(regexpStr); // Call onCharacter hook
  37         } catch {
  38
  39             // Ignore syntax errors in RegExp.
  40         }
  41         return this._controlChars;
  42     }
  43 })();
  44
  45 //------------------------------------------------------------------------------
  46 // Rule Definition
  47 //------------------------------------------------------------------------------
  48
  49 /** @type {import('../shared/types').Rule} */
  50 module.exports = {
  51     meta: {
  52         type: "problem",
  53
  54         docs: {
  55             description: "disallow control characters in regular expressions",
  56             recommended: true,
  57             url: "https://eslint.org/docs/rules/no-control-regex"
  58         },
  59
  60         schema: [],
  61
  62         messages: {
  63             unexpected: "Unexpected control character(s) in regular expression: {{controlChars}}."
  64         }
  65     },
  66
  67     create(context) {
  68
  69         /**
  70          * Get the regex expression
  71          * @param {ASTNode} node node to evaluate
  72          * @returns {RegExp|null} Regex if found else null
  73          * @private
  74          */
  75         function getRegExpPattern(node) {
  76             if (node.regex) {
  77                 return node.regex.pattern;
  78             }
  79             if (typeof node.value === "string" &&
  80                 (node.parent.type === "NewExpression" || node.parent.type === "CallExpression") &&
  81                 node.parent.callee.type === "Identifier" &&
  82                 node.parent.callee.name === "RegExp" &&
  83                 node.parent.arguments[0] === node
  84             ) {
  85                 return node.value;
  86             }
  87
  88             return null;
  89         }
  90
  91         return {
  92             Literal(node) {
  93                 const pattern = getRegExpPattern(node);
  94
  95                 if (pattern) {
  96                     const controlCharacters = collector.collectControlChars(pattern);
  97
  98                     if (controlCharacters.length > 0) {
  99                         context.report({
 100                             node,
 101                             messageId: "unexpected",
 102                             data: {
 103                                 controlChars: controlCharacters.join(", ")
 104                             }
 105                         });
 106                     }
 107                 }
 108             }
 109         };
 110
 111     }
 112 };