no-control-regex.js

   1 /**
   2  * @fileoverview Rule to forbid control charactes 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.ecmaVersion = 2018;
  12         this._source = "";
  13         this._controlChars = [];
  14         this._validator = new RegExpValidator(this);
  15     }
  16
  17     onPatternEnter() {
  18         this._controlChars = [];
  19     }
  20
  21     onCharacter(start, end, cp) {
  22         if (cp >= 0x00 &&
  23             cp <= 0x1F &&
  24             (
  25                 this._source.codePointAt(start) === cp ||
  26                 this._source.slice(start, end).startsWith("\\x") ||
  27                 this._source.slice(start, end).startsWith("\\u")
  28             )
  29         ) {
  30             this._controlChars.push(`\\x${`0${cp.toString(16)}`.slice(-2)}`);
  31         }
  32     }
  33
  34     collectControlChars(regexpStr) {
  35         try {
  36             this._source = regexpStr;
  37             this._validator.validatePattern(regexpStr); // Call onCharacter hook
  38         } catch (err) {
  39
  40             // Ignore syntax errors in RegExp.
  41         }
  42         return this._controlChars;
  43     }
  44 })();
  45
  46 //------------------------------------------------------------------------------
  47 // Rule Definition
  48 //------------------------------------------------------------------------------
  49
  50 module.exports = {
  51     meta: {
  52         type: "problem",
  53
  54         docs: {
  55             description: "disallow control characters in regular expressions",
  56             category: "Possible Errors",
  57             recommended: true,
  58             url: "https://eslint.org/docs/rules/no-control-regex"
  59         },
  60
  61         schema: [],
  62
  63         messages: {
  64             unexpected: "Unexpected control character(s) in regular expression: {{controlChars}}."
  65         }
  66     },
  67
  68     create(context) {
  69
  70         /**
  71          * Get the regex expression
  72          * @param {ASTNode} node node to evaluate
  73          * @returns {RegExp|null} Regex if found else null
  74          * @private
  75          */
  76         function getRegExpPattern(node) {
  77             if (node.regex) {
  78                 return node.regex.pattern;
  79             }
  80             if (typeof node.value === "string" &&
  81                 (node.parent.type === "NewExpression" || node.parent.type === "CallExpression") &&
  82                 node.parent.callee.type === "Identifier" &&
  83                 node.parent.callee.name === "RegExp" &&
  84                 node.parent.arguments[0] === node
  85             ) {
  86                 return node.value;
  87             }
  88
  89             return null;
  90         }
  91
  92         return {
  93             Literal(node) {
  94                 const pattern = getRegExpPattern(node);
  95
  96                 if (pattern) {
  97                     const controlCharacters = collector.collectControlChars(pattern);
  98
  99                     if (controlCharacters.length > 0) {
 100                         context.report({
 101                             node,
 102                             messageId: "unexpected",
 103                             data: {
 104                                 controlChars: controlCharacters.join(", ")
 105                             }
 106                         });
 107                     }
 108                 }
 109             }
 110         };
 111
 112     }
 113 };