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, flags) {
  34         const uFlag = typeof flags === "string" && flags.includes("u");
  35
  36         try {
  37             this._source = regexpStr;
  38             this._validator.validatePattern(regexpStr, void 0, void 0, uFlag); // Call onCharacter hook
  39         } catch {
  40
  41             // Ignore syntax errors in RegExp.
  42         }
  43         return this._controlChars;
  44     }
  45 })();
  46
  47 //------------------------------------------------------------------------------
  48 // Rule Definition
  49 //------------------------------------------------------------------------------
  50
  51 /** @type {import('../shared/types').Rule} */
  52 module.exports = {
  53     meta: {
  54         type: "problem",
  55
  56         docs: {
  57             description: "Disallow control characters in regular expressions",
  58             recommended: true,
  59             url: "https://eslint.org/docs/rules/no-control-regex"
  60         },
  61
  62         schema: [],
  63
  64         messages: {
  65             unexpected: "Unexpected control character(s) in regular expression: {{controlChars}}."
  66         }
  67     },
  68
  69     create(context) {
  70
  71         /**
  72          * Get the regex expression
  73          * @param {ASTNode} node `Literal` node to evaluate
  74          * @returns {{ pattern: string, flags: string | null } | null} Regex if found (the given node is either a regex literal
  75          * or a string literal that is the pattern argument of a RegExp constructor call). Otherwise `null`. If flags cannot be determined,
  76          * the `flags` property will be `null`.
  77          * @private
  78          */
  79         function getRegExp(node) {
  80             if (node.regex) {
  81                 return node.regex;
  82             }
  83             if (typeof node.value === "string" &&
  84                 (node.parent.type === "NewExpression" || node.parent.type === "CallExpression") &&
  85                 node.parent.callee.type === "Identifier" &&
  86                 node.parent.callee.name === "RegExp" &&
  87                 node.parent.arguments[0] === node
  88             ) {
  89                 const pattern = node.value;
  90                 const flags =
  91                     node.parent.arguments.length > 1 &&
  92                     node.parent.arguments[1].type === "Literal" &&
  93                     typeof node.parent.arguments[1].value === "string"
  94                         ? node.parent.arguments[1].value
  95                         : null;
  96
  97                 return { pattern, flags };
  98             }
  99
 100             return null;
 101         }
 102
 103         return {
 104             Literal(node) {
 105                 const regExp = getRegExp(node);
 106
 107                 if (regExp) {
 108                     const { pattern, flags } = regExp;
 109                     const controlCharacters = collector.collectControlChars(pattern, flags);
 110
 111                     if (controlCharacters.length > 0) {
 112                         context.report({
 113                             node,
 114                             messageId: "unexpected",
 115                             data: {
 116                                 controlChars: controlCharacters.join(", ")
 117                             }
 118                         });
 119                     }
 120                 }
 121             }
 122         };
 123
 124     }
 125 };