Current File : /home/vacivi36/SiteVacivitta/vacivitta/node_modules/eslint/lib/rules/no-useless-escape.js
/**
* @fileoverview Look for useless escapes in strings and regexes
* @author Onur Temizkan
*/
"use strict";
const astUtils = require("./utils/ast-utils");
const { RegExpParser, visitRegExpAST } = require("@eslint-community/regexpp");
/**
* @typedef {import('@eslint-community/regexpp').AST.CharacterClass} CharacterClass
* @typedef {import('@eslint-community/regexpp').AST.ExpressionCharacterClass} ExpressionCharacterClass
*/
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/**
* Returns the union of two sets.
* @param {Set} setA The first set
* @param {Set} setB The second set
* @returns {Set} The union of the two sets
*/
function union(setA, setB) {
return new Set(
(function* () {
yield* setA;
yield* setB;
})(),
);
}
const VALID_STRING_ESCAPES = union(new Set("\\nrvtbfux"), astUtils.LINEBREAKS);
const REGEX_GENERAL_ESCAPES = new Set("\\bcdDfnpPrsStvwWxu0123456789]");
const REGEX_NON_CHARCLASS_ESCAPES = union(
REGEX_GENERAL_ESCAPES,
new Set("^/.$*+?[{}|()Bk"),
);
/*
* Set of characters that require escaping in character classes in `unicodeSets` mode.
* ( ) [ ] { } / - \ | are ClassSetSyntaxCharacter
*/
const REGEX_CLASSSET_CHARACTER_ESCAPES = union(
REGEX_GENERAL_ESCAPES,
new Set("q/[{}|()-"),
);
/*
* A single character set of ClassSetReservedDoublePunctuator.
* && !! ## $$ %% ** ++ ,, .. :: ;; << == >> ?? @@ ^^ `` ~~ are ClassSetReservedDoublePunctuator
*/
const REGEX_CLASS_SET_RESERVED_DOUBLE_PUNCTUATOR = new Set(
"!#$%&*+,.:;<=>?@^`~",
);
/** @type {import('../types').Rule.RuleModule} */
module.exports = {
meta: {
type: "suggestion",
defaultOptions: [
{
allowRegexCharacters: [],
},
],
docs: {
description: "Disallow unnecessary escape characters",
recommended: true,
url: "https://eslint.org/docs/latest/rules/no-useless-escape",
},
hasSuggestions: true,
messages: {
unnecessaryEscape: "Unnecessary escape character: \\{{character}}.",
removeEscape:
"Remove the `\\`. This maintains the current functionality.",
removeEscapeDoNotKeepSemantics:
"Remove the `\\` if it was inserted by mistake.",
escapeBackslash:
"Replace the `\\` with `\\\\` to include the actual backslash character.",
},
schema: [
{
type: "object",
properties: {
allowRegexCharacters: {
type: "array",
items: {
type: "string",
},
uniqueItems: true,
},
},
additionalProperties: false,
},
],
},
create(context) {
const sourceCode = context.sourceCode;
const [{ allowRegexCharacters }] = context.options;
const parser = new RegExpParser();
/**
* Reports a node
* @param {ASTNode} node The node to report
* @param {number} startOffset The backslash's offset from the start of the node
* @param {string} character The uselessly escaped character (not including the backslash)
* @param {boolean} [disableEscapeBackslashSuggest] `true` if escapeBackslash suggestion should be turned off.
* @returns {void}
*/
function report(
node,
startOffset,
character,
disableEscapeBackslashSuggest,
) {
const rangeStart = node.range[0] + startOffset;
const range = [rangeStart, rangeStart + 1];
const start = sourceCode.getLocFromIndex(rangeStart);
context.report({
node,
loc: {
start,
end: { line: start.line, column: start.column + 1 },
},
messageId: "unnecessaryEscape",
data: { character },
suggest: [
{
// Removing unnecessary `\` characters in a directive is not guaranteed to maintain functionality.
messageId: astUtils.isDirective(node.parent)
? "removeEscapeDoNotKeepSemantics"
: "removeEscape",
fix(fixer) {
return fixer.removeRange(range);
},
},
...(disableEscapeBackslashSuggest
? []
: [
{
messageId: "escapeBackslash",
fix(fixer) {
return fixer.insertTextBeforeRange(
range,
"\\",
);
},
},
]),
],
});
}
/**
* Checks if the escape character in given string slice is unnecessary.
* @private
* @param {ASTNode} node node to validate.
* @param {string} match string slice to validate.
* @returns {void}
*/
function validateString(node, match) {
const isTemplateElement = node.type === "TemplateElement";
const escapedChar = match[0][1];
let isUnnecessaryEscape = !VALID_STRING_ESCAPES.has(escapedChar);
let isQuoteEscape;
if (isTemplateElement) {
isQuoteEscape = escapedChar === "`";
if (escapedChar === "$") {
// Warn if `\$` is not followed by `{`
isUnnecessaryEscape = match.input[match.index + 2] !== "{";
} else if (escapedChar === "{") {
/*
* Warn if `\{` is not preceded by `$`. If preceded by `$`, escaping
* is necessary and the rule should not warn. If preceded by `/$`, the rule
* will warn for the `/$` instead, as it is the first unnecessarily escaped character.
*/
isUnnecessaryEscape = match.input[match.index - 1] !== "$";
}
} else {
isQuoteEscape = escapedChar === node.raw[0];
}
if (isUnnecessaryEscape && !isQuoteEscape) {
report(node, match.index, match[0].slice(1));
}
}
/**
* Checks if the escape character in given regexp is unnecessary.
* @private
* @param {ASTNode} node node to validate.
* @returns {void}
*/
function validateRegExp(node) {
const { pattern, flags } = node.regex;
let patternNode;
const unicode = flags.includes("u");
const unicodeSets = flags.includes("v");
try {
patternNode = parser.parsePattern(pattern, 0, pattern.length, {
unicode,
unicodeSets,
});
} catch {
// Ignore regular expressions with syntax errors
return;
}
/** @type {(CharacterClass | ExpressionCharacterClass)[]} */
const characterClassStack = [];
visitRegExpAST(patternNode, {
onCharacterClassEnter: characterClassNode =>
characterClassStack.unshift(characterClassNode),
onCharacterClassLeave: () => characterClassStack.shift(),
onExpressionCharacterClassEnter: characterClassNode =>
characterClassStack.unshift(characterClassNode),
onExpressionCharacterClassLeave: () =>
characterClassStack.shift(),
onCharacterEnter(characterNode) {
if (!characterNode.raw.startsWith("\\")) {
// It's not an escaped character.
return;
}
const escapedChar = characterNode.raw.slice(1);
if (
escapedChar !==
String.fromCodePoint(characterNode.value) ||
allowRegexCharacters.includes(escapedChar)
) {
// It's a valid escape.
return;
}
let allowedEscapes;
if (characterClassStack.length) {
allowedEscapes = unicodeSets
? REGEX_CLASSSET_CHARACTER_ESCAPES
: REGEX_GENERAL_ESCAPES;
} else {
allowedEscapes = REGEX_NON_CHARCLASS_ESCAPES;
}
if (allowedEscapes.has(escapedChar)) {
return;
}
const reportedIndex = characterNode.start + 1;
let disableEscapeBackslashSuggest = false;
if (characterClassStack.length) {
const characterClassNode = characterClassStack[0];
if (escapedChar === "^") {
/*
* The '^' character is also a special case; it must always be escaped outside of character classes, but
* it only needs to be escaped in character classes if it's at the beginning of the character class. To
* account for this, consider it to be a valid escape character outside of character classes, and filter
* out '^' characters that appear at the start of a character class.
*/
if (
characterClassNode.start + 1 ===
characterNode.start
) {
return;
}
}
if (!unicodeSets) {
if (escapedChar === "-") {
/*
* The '-' character is a special case, because it's only valid to escape it if it's in a character
* class, and is not at either edge of the character class. To account for this, don't consider '-'
* characters to be valid in general, and filter out '-' characters that appear in the middle of a
* character class.
*/
if (
characterClassNode.start + 1 !==
characterNode.start &&
characterNode.end !==
characterClassNode.end - 1
) {
return;
}
}
} else {
// unicodeSets mode
if (
REGEX_CLASS_SET_RESERVED_DOUBLE_PUNCTUATOR.has(
escapedChar,
)
) {
// Escaping is valid if it is a ClassSetReservedDoublePunctuator.
if (
pattern[characterNode.end] === escapedChar
) {
return;
}
if (
pattern[characterNode.start - 1] ===
escapedChar
) {
if (escapedChar !== "^") {
return;
}
// If the previous character is a `negate` caret(`^`), escape to caret is unnecessary.
if (!characterClassNode.negate) {
return;
}
const negateCaretIndex =
characterClassNode.start + 1;
if (
negateCaretIndex <
characterNode.start - 1
) {
return;
}
}
}
if (
characterNode.parent.type ===
"ClassIntersection" ||
characterNode.parent.type === "ClassSubtraction"
) {
disableEscapeBackslashSuggest = true;
}
}
}
report(
node,
reportedIndex,
escapedChar,
disableEscapeBackslashSuggest,
);
},
});
}
/**
* Checks if a node has an escape.
* @param {ASTNode} node node to check.
* @returns {void}
*/
function check(node) {
const isTemplateElement = node.type === "TemplateElement";
if (
isTemplateElement &&
node.parent &&
node.parent.parent &&
node.parent.parent.type === "TaggedTemplateExpression" &&
node.parent === node.parent.parent.quasi
) {
// Don't report tagged template literals, because the backslash character is accessible to the tag function.
return;
}
if (typeof node.value === "string" || isTemplateElement) {
/*
* JSXAttribute doesn't have any escape sequence: https://facebook.github.io/jsx/.
* In addition, backticks are not supported by JSX yet: https://github.com/facebook/jsx/issues/25.
*/
if (
node.parent.type === "JSXAttribute" ||
node.parent.type === "JSXElement" ||
node.parent.type === "JSXFragment"
) {
return;
}
const value = isTemplateElement
? sourceCode.getText(node)
: node.raw;
const pattern = /\\[^\d]/gu;
let match;
while ((match = pattern.exec(value))) {
validateString(node, match);
}
} else if (node.regex) {
validateRegExp(node);
}
}
return {
Literal: check,
TemplateElement: check,
};
},
};
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