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/**
* @fileoverview Rule to disallow use of the `RegExp` constructor in favor of regular expression literals
* @author Milos Djermanovic
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const astUtils = require("./utils/ast-utils");
const { CALL, CONSTRUCT, ReferenceTracker, findVariable } = require("eslint-utils");
const { RegExpValidator, visitRegExpAST, RegExpParser } = require("regexpp");
const { canTokensBeAdjacent } = require("./utils/ast-utils");
//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------
const REGEXPP_LATEST_ECMA_VERSION = 2022;
/**
* Determines whether the given node is a string literal.
* @param {ASTNode} node Node to check.
* @returns {boolean} True if the node is a string literal.
*/
function isStringLiteral(node) {
return node.type === "Literal" && typeof node.value === "string";
}
/**
* Determines whether the given node is a regex literal.
* @param {ASTNode} node Node to check.
* @returns {boolean} True if the node is a regex literal.
*/
function isRegexLiteral(node) {
return node.type === "Literal" && Object.prototype.hasOwnProperty.call(node, "regex");
}
/**
* Determines whether the given node is a template literal without expressions.
* @param {ASTNode} node Node to check.
* @returns {boolean} True if the node is a template literal without expressions.
*/
function isStaticTemplateLiteral(node) {
return node.type === "TemplateLiteral" && node.expressions.length === 0;
}
const validPrecedingTokens = new Set([
"(",
";",
"[",
",",
"=",
"+",
"*",
"-",
"?",
"~",
"%",
"**",
"!",
"typeof",
"instanceof",
"&&",
"||",
"??",
"return",
"...",
"delete",
"void",
"in",
"<",
">",
"<=",
">=",
"==",
"===",
"!=",
"!==",
"<<",
">>",
">>>",
"&",
"|",
"^",
":",
"{",
"=>",
"*=",
"<<=",
">>=",
">>>=",
"^=",
"|=",
"&=",
"??=",
"||=",
"&&=",
"**=",
"+=",
"-=",
"/=",
"%=",
"/",
"do",
"break",
"continue",
"debugger",
"case",
"throw"
]);
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/** @type {import('../shared/types').Rule} */
module.exports = {
meta: {
type: "suggestion",
docs: {
description: "Disallow use of the `RegExp` constructor in favor of regular expression literals",
recommended: false,
url: "https://eslint.org/docs/rules/prefer-regex-literals"
},
hasSuggestions: true,
schema: [
{
type: "object",
properties: {
disallowRedundantWrapping: {
type: "boolean",
default: false
}
},
additionalProperties: false
}
],
messages: {
unexpectedRegExp: "Use a regular expression literal instead of the 'RegExp' constructor.",
replaceWithLiteral: "Replace with an equivalent regular expression literal.",
unexpectedRedundantRegExp: "Regular expression literal is unnecessarily wrapped within a 'RegExp' constructor.",
unexpectedRedundantRegExpWithFlags: "Use regular expression literal with flags instead of the 'RegExp' constructor."
}
},
create(context) {
const [{ disallowRedundantWrapping = false } = {}] = context.options;
const sourceCode = context.getSourceCode();
/**
* Determines whether the given identifier node is a reference to a global variable.
* @param {ASTNode} node `Identifier` node to check.
* @returns {boolean} True if the identifier is a reference to a global variable.
*/
function isGlobalReference(node) {
const scope = context.getScope();
const variable = findVariable(scope, node);
return variable !== null && variable.scope.type === "global" && variable.defs.length === 0;
}
/**
* Determines whether the given node is a String.raw`` tagged template expression
* with a static template literal.
* @param {ASTNode} node Node to check.
* @returns {boolean} True if the node is String.raw`` with a static template.
*/
function isStringRawTaggedStaticTemplateLiteral(node) {
return node.type === "TaggedTemplateExpression" &&
astUtils.isSpecificMemberAccess(node.tag, "String", "raw") &&
isGlobalReference(astUtils.skipChainExpression(node.tag).object) &&
isStaticTemplateLiteral(node.quasi);
}
/**
* Gets the value of a string
* @param {ASTNode} node The node to get the string of.
* @returns {string|null} The value of the node.
*/
function getStringValue(node) {
if (isStringLiteral(node)) {
return node.value;
}
if (isStaticTemplateLiteral(node)) {
return node.quasis[0].value.cooked;
}
if (isStringRawTaggedStaticTemplateLiteral(node)) {
return node.quasi.quasis[0].value.raw;
}
return null;
}
/**
* Determines whether the given node is considered to be a static string by the logic of this rule.
* @param {ASTNode} node Node to check.
* @returns {boolean} True if the node is a static string.
*/
function isStaticString(node) {
return isStringLiteral(node) ||
isStaticTemplateLiteral(node) ||
isStringRawTaggedStaticTemplateLiteral(node);
}
/**
* Determines whether the relevant arguments of the given are all static string literals.
* @param {ASTNode} node Node to check.
* @returns {boolean} True if all arguments are static strings.
*/
function hasOnlyStaticStringArguments(node) {
const args = node.arguments;
if ((args.length === 1 || args.length === 2) && args.every(isStaticString)) {
return true;
}
return false;
}
/**
* Determines whether the arguments of the given node indicate that a regex literal is unnecessarily wrapped.
* @param {ASTNode} node Node to check.
* @returns {boolean} True if the node already contains a regex literal argument.
*/
function isUnnecessarilyWrappedRegexLiteral(node) {
const args = node.arguments;
if (args.length === 1 && isRegexLiteral(args[0])) {
return true;
}
if (args.length === 2 && isRegexLiteral(args[0]) && isStaticString(args[1])) {
return true;
}
return false;
}
/**
* Returns a ecmaVersion compatible for regexpp.
* @param {any} ecmaVersion The ecmaVersion to convert.
* @returns {import("regexpp/ecma-versions").EcmaVersion} The resulting ecmaVersion compatible for regexpp.
*/
function getRegexppEcmaVersion(ecmaVersion) {
if (typeof ecmaVersion !== "number" || ecmaVersion <= 5) {
return 5;
}
return Math.min(ecmaVersion + 2009, REGEXPP_LATEST_ECMA_VERSION);
}
/**
* Makes a character escaped or else returns null.
* @param {string} character The character to escape.
* @returns {string} The resulting escaped character.
*/
function resolveEscapes(character) {
switch (character) {
case "\n":
case "\\\n":
return "\\n";
case "\r":
case "\\\r":
return "\\r";
case "\t":
case "\\\t":
return "\\t";
case "\v":
case "\\\v":
return "\\v";
case "\f":
case "\\\f":
return "\\f";
case "/":
return "\\/";
default:
return null;
}
}
return {
Program() {
const scope = context.getScope();
const tracker = new ReferenceTracker(scope);
const traceMap = {
RegExp: {
[CALL]: true,
[CONSTRUCT]: true
}
};
for (const { node } of tracker.iterateGlobalReferences(traceMap)) {
if (disallowRedundantWrapping && isUnnecessarilyWrappedRegexLiteral(node)) {
if (node.arguments.length === 2) {
context.report({ node, messageId: "unexpectedRedundantRegExpWithFlags" });
} else {
context.report({ node, messageId: "unexpectedRedundantRegExp" });
}
} else if (hasOnlyStaticStringArguments(node)) {
let regexContent = getStringValue(node.arguments[0]);
let noFix = false;
let flags;
if (node.arguments[1]) {
flags = getStringValue(node.arguments[1]);
}
const regexppEcmaVersion = getRegexppEcmaVersion(context.parserOptions.ecmaVersion);
const RegExpValidatorInstance = new RegExpValidator({ ecmaVersion: regexppEcmaVersion });
try {
RegExpValidatorInstance.validatePattern(regexContent, 0, regexContent.length, flags ? flags.includes("u") : false);
if (flags) {
RegExpValidatorInstance.validateFlags(flags);
}
} catch {
noFix = true;
}
const tokenBefore = sourceCode.getTokenBefore(node);
if (tokenBefore && !validPrecedingTokens.has(tokenBefore.value)) {
noFix = true;
}
if (!/^[-a-zA-Z0-9\\[\](){} \t\r\n\v\f!@#$%^&*+^_=/~`.><?,'"|:;]*$/u.test(regexContent)) {
noFix = true;
}
if (sourceCode.getCommentsInside(node).length > 0) {
noFix = true;
}
if (regexContent && !noFix) {
let charIncrease = 0;
const ast = new RegExpParser({ ecmaVersion: regexppEcmaVersion }).parsePattern(regexContent, 0, regexContent.length, flags ? flags.includes("u") : false);
visitRegExpAST(ast, {
onCharacterEnter(characterNode) {
const escaped = resolveEscapes(characterNode.raw);
if (escaped) {
regexContent =
regexContent.slice(0, characterNode.start + charIncrease) +
escaped +
regexContent.slice(characterNode.end + charIncrease);
if (characterNode.raw.length === 1) {
charIncrease += 1;
}
}
}
});
}
const newRegExpValue = `/${regexContent || "(?:)"}/${flags || ""}`;
context.report({
node,
messageId: "unexpectedRegExp",
suggest: noFix ? [] : [{
messageId: "replaceWithLiteral",
fix(fixer) {
const tokenAfter = sourceCode.getTokenAfter(node);
return fixer.replaceText(
node,
(tokenBefore && !canTokensBeAdjacent(tokenBefore, newRegExpValue) && tokenBefore.range[1] === node.range[0] ? " " : "") +
newRegExpValue +
(tokenAfter && !canTokensBeAdjacent(newRegExpValue, tokenAfter) && node.range[1] === tokenAfter.range[0] ? " " : "")
);
}
}]
});
}
}
}
};
}
};