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/**
* @fileoverview Rule to forbid control characters from regular expressions.
* @author Nicholas C. Zakas
*/
"use strict";
const RegExpValidator = require("@eslint-community/regexpp").RegExpValidator;
const collector = new (class {
constructor() {
this._source = "";
this._controlChars = [];
this._validator = new RegExpValidator(this);
}
onPatternEnter() {
/*
* `RegExpValidator` may parse the pattern twice in one `validatePattern`.
* So `this._controlChars` should be cleared here as well.
*
* For example, the `/(?<a>\x1f)/` regex will parse the pattern twice.
* This is based on the content described in Annex B.
* If the regex contains a `GroupName` and the `u` flag is not used, `ParseText` will be called twice.
* See https://tc39.es/ecma262/2023/multipage/additional-ecmascript-features-for-web-browsers.html#sec-parsepattern-annexb
*/
this._controlChars = [];
}
onCharacter(start, end, cp) {
if (cp >= 0x00 &&
cp <= 0x1F &&
(
this._source.codePointAt(start) === cp ||
this._source.slice(start, end).startsWith("\\x") ||
this._source.slice(start, end).startsWith("\\u")
)
) {
this._controlChars.push(`\\x${`0${cp.toString(16)}`.slice(-2)}`);
}
}
collectControlChars(regexpStr, flags) {
const uFlag = typeof flags === "string" && flags.includes("u");
const vFlag = typeof flags === "string" && flags.includes("v");
this._controlChars = [];
this._source = regexpStr;
try {
this._validator.validatePattern(regexpStr, void 0, void 0, { unicode: uFlag, unicodeSets: vFlag }); // Call onCharacter hook
} catch {
// Ignore syntax errors in RegExp.
}
return this._controlChars;
}
})();
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/** @type {import('../shared/types').Rule} */
module.exports = {
meta: {
type: "problem",
docs: {
description: "Disallow control characters in regular expressions",
recommended: true,
url: "https://eslint.org/docs/latest/rules/no-control-regex"
},
schema: [],
messages: {
unexpected: "Unexpected control character(s) in regular expression: {{controlChars}}."
}
},
create(context) {
/**
* Get the regex expression
* @param {ASTNode} node `Literal` node to evaluate
* @returns {{ pattern: string, flags: string | null } | null} Regex if found (the given node is either a regex literal
* or a string literal that is the pattern argument of a RegExp constructor call). Otherwise `null`. If flags cannot be determined,
* the `flags` property will be `null`.
* @private
*/
function getRegExp(node) {
if (node.regex) {
return node.regex;
}
if (typeof node.value === "string" &&
(node.parent.type === "NewExpression" || node.parent.type === "CallExpression") &&
node.parent.callee.type === "Identifier" &&
node.parent.callee.name === "RegExp" &&
node.parent.arguments[0] === node
) {
const pattern = node.value;
const flags =
node.parent.arguments.length > 1 &&
node.parent.arguments[1].type === "Literal" &&
typeof node.parent.arguments[1].value === "string"
? node.parent.arguments[1].value
: null;
return { pattern, flags };
}
return null;
}
return {
Literal(node) {
const regExp = getRegExp(node);
if (regExp) {
const { pattern, flags } = regExp;
const controlCharacters = collector.collectControlChars(pattern, flags);
if (controlCharacters.length > 0) {
context.report({
node,
messageId: "unexpected",
data: {
controlChars: controlCharacters.join(", ")
}
});
}
}
}
};
}
};