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/**
* @author Toru Nagashima <https://github.com/mysticatea>
*/
"use strict";
const { CALL, CONSTRUCT, ReferenceTracker, getStringIfConstant } = require("eslint-utils");
const { RegExpParser, visitRegExpAST } = require("regexpp");
const { isCombiningCharacter, isEmojiModifier, isRegionalIndicatorSymbol, isSurrogatePair } = require("./utils/unicode");
//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------
/**
* Iterate character sequences of a given nodes.
*
* CharacterClassRange syntax can steal a part of character sequence,
* so this function reverts CharacterClassRange syntax and restore the sequence.
*
* @param {regexpp.AST.CharacterClassElement[]} nodes The node list to iterate character sequences.
* @returns {IterableIterator<number[]>} The list of character sequences.
*/
function *iterateCharacterSequence(nodes) {
let seq = [];
for (const node of nodes) {
switch (node.type) {
case "Character":
seq.push(node.value);
break;
case "CharacterClassRange":
seq.push(node.min.value);
yield seq;
seq = [node.max.value];
break;
case "CharacterSet":
if (seq.length > 0) {
yield seq;
seq = [];
}
break;
// no default
}
}
if (seq.length > 0) {
yield seq;
}
}
const hasCharacterSequence = {
surrogatePairWithoutUFlag(chars) {
return chars.some((c, i) => i !== 0 && isSurrogatePair(chars[i - 1], c));
},
combiningClass(chars) {
return chars.some((c, i) => (
i !== 0 &&
isCombiningCharacter(c) &&
!isCombiningCharacter(chars[i - 1])
));
},
emojiModifier(chars) {
return chars.some((c, i) => (
i !== 0 &&
isEmojiModifier(c) &&
!isEmojiModifier(chars[i - 1])
));
},
regionalIndicatorSymbol(chars) {
return chars.some((c, i) => (
i !== 0 &&
isRegionalIndicatorSymbol(c) &&
isRegionalIndicatorSymbol(chars[i - 1])
));
},
zwj(chars) {
const lastIndex = chars.length - 1;
return chars.some((c, i) => (
i !== 0 &&
i !== lastIndex &&
c === 0x200d &&
chars[i - 1] !== 0x200d &&
chars[i + 1] !== 0x200d
));
}
};
const kinds = Object.keys(hasCharacterSequence);
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = {
meta: {
type: "problem",
docs: {
description: "disallow characters which are made with multiple code points in character class syntax",
category: "Possible Errors",
recommended: true,
url: "https://eslint.org/docs/rules/no-misleading-character-class"
},
schema: [],
messages: {
surrogatePairWithoutUFlag: "Unexpected surrogate pair in character class. Use 'u' flag.",
combiningClass: "Unexpected combined character in character class.",
emojiModifier: "Unexpected modified Emoji in character class.",
regionalIndicatorSymbol: "Unexpected national flag in character class.",
zwj: "Unexpected joined character sequence in character class."
}
},
create(context) {
const parser = new RegExpParser();
/**
* Verify a given regular expression.
* @param {Node} node The node to report.
* @param {string} pattern The regular expression pattern to verify.
* @param {string} flags The flags of the regular expression.
* @returns {void}
*/
function verify(node, pattern, flags) {
const patternNode = parser.parsePattern(
pattern,
0,
pattern.length,
flags.includes("u")
);
const has = {
surrogatePairWithoutUFlag: false,
combiningClass: false,
variationSelector: false,
emojiModifier: false,
regionalIndicatorSymbol: false,
zwj: false
};
visitRegExpAST(patternNode, {
onCharacterClassEnter(ccNode) {
for (const chars of iterateCharacterSequence(ccNode.elements)) {
for (const kind of kinds) {
has[kind] = has[kind] || hasCharacterSequence[kind](chars);
}
}
}
});
for (const kind of kinds) {
if (has[kind]) {
context.report({ node, messageId: kind });
}
}
}
return {
"Literal[regex]"(node) {
verify(node, node.regex.pattern, node.regex.flags);
},
"Program"() {
const scope = context.getScope();
const tracker = new ReferenceTracker(scope);
/*
* Iterate calls of RegExp.
* E.g., `new RegExp()`, `RegExp()`, `new window.RegExp()`,
* `const {RegExp: a} = window; new a()`, etc...
*/
for (const { node } of tracker.iterateGlobalReferences({
RegExp: { [CALL]: true, [CONSTRUCT]: true }
})) {
const [patternNode, flagsNode] = node.arguments;
const pattern = getStringIfConstant(patternNode, scope);
const flags = getStringIfConstant(flagsNode, scope);
if (typeof pattern === "string") {
verify(node, pattern, flags || "");
}
}
}
};
}
};
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