255 lines
9.8 KiB
JavaScript
255 lines
9.8 KiB
JavaScript
|
/**
|
||
|
|
* @fileoverview Look for useless escapes in strings and regexes
|
||
|
|
* @author Onur Temizkan
|
||
|
|
*/
|
||
|
|
|
||
|
|
"use strict";
|
||
|
|
|
||
|
|
const astUtils = require("./utils/ast-utils");
|
||
|
|
|
||
|
|
//------------------------------------------------------------------------------
|
||
|
|
// 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"));
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Parses a regular expression into a list of characters with character class info.
|
||
|
|
* @param {string} regExpText The raw text used to create the regular expression
|
||
|
|
* @returns {Object[]} A list of characters, each with info on escaping and whether they're in a character class.
|
||
|
|
* @example
|
||
|
|
*
|
||
|
|
* parseRegExp("a\\b[cd-]");
|
||
|
|
*
|
||
|
|
* // returns:
|
||
|
|
* [
|
||
|
|
* { text: "a", index: 0, escaped: false, inCharClass: false, startsCharClass: false, endsCharClass: false },
|
||
|
|
* { text: "b", index: 2, escaped: true, inCharClass: false, startsCharClass: false, endsCharClass: false },
|
||
|
|
* { text: "c", index: 4, escaped: false, inCharClass: true, startsCharClass: true, endsCharClass: false },
|
||
|
|
* { text: "d", index: 5, escaped: false, inCharClass: true, startsCharClass: false, endsCharClass: false },
|
||
|
|
* { text: "-", index: 6, escaped: false, inCharClass: true, startsCharClass: false, endsCharClass: false }
|
||
|
|
* ];
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
function parseRegExp(regExpText) {
|
||
|
|
const charList = [];
|
||
|
|
|
||
|
|
regExpText.split("").reduce((state, char, index) => {
|
||
|
|
if (!state.escapeNextChar) {
|
||
|
|
if (char === "\\") {
|
||
|
|
return Object.assign(state, { escapeNextChar: true });
|
||
|
|
}
|
||
|
|
if (char === "[" && !state.inCharClass) {
|
||
|
|
return Object.assign(state, { inCharClass: true, startingCharClass: true });
|
||
|
|
}
|
||
|
|
if (char === "]" && state.inCharClass) {
|
||
|
|
if (charList.length && charList[charList.length - 1].inCharClass) {
|
||
|
|
charList[charList.length - 1].endsCharClass = true;
|
||
|
|
}
|
||
|
|
return Object.assign(state, { inCharClass: false, startingCharClass: false });
|
||
|
|
}
|
||
|
|
}
|
||
|
|
charList.push({
|
||
|
|
text: char,
|
||
|
|
index,
|
||
|
|
escaped: state.escapeNextChar,
|
||
|
|
inCharClass: state.inCharClass,
|
||
|
|
startsCharClass: state.startingCharClass,
|
||
|
|
endsCharClass: false
|
||
|
|
});
|
||
|
|
return Object.assign(state, { escapeNextChar: false, startingCharClass: false });
|
||
|
|
}, { escapeNextChar: false, inCharClass: false, startingCharClass: false });
|
||
|
|
|
||
|
|
return charList;
|
||
|
|
}
|
||
|
|
|
||
|
|
/** @type {import('../shared/types').Rule} */
|
||
|
|
module.exports = {
|
||
|
|
meta: {
|
||
|
|
type: "suggestion",
|
||
|
|
|
||
|
|
docs: {
|
||
|
|
description: "disallow unnecessary escape characters",
|
||
|
|
recommended: true,
|
||
|
|
url: "https://eslint.org/docs/rules/no-useless-escape"
|
||
|
|
},
|
||
|
|
|
||
|
|
hasSuggestions: true,
|
||
|
|
|
||
|
|
messages: {
|
||
|
|
unnecessaryEscape: "Unnecessary escape character: \\{{character}}.",
|
||
|
|
removeEscape: "Remove the `\\`. This maintains the current functionality.",
|
||
|
|
escapeBackslash: "Replace the `\\` with `\\\\` to include the actual backslash character."
|
||
|
|
},
|
||
|
|
|
||
|
|
schema: []
|
||
|
|
},
|
||
|
|
|
||
|
|
create(context) {
|
||
|
|
const sourceCode = context.getSourceCode();
|
||
|
|
|
||
|
|
/**
|
||
|
|
* 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)
|
||
|
|
* @returns {void}
|
||
|
|
*/
|
||
|
|
function report(node, startOffset, character) {
|
||
|
|
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: [
|
||
|
|
{
|
||
|
|
messageId: "removeEscape",
|
||
|
|
fix(fixer) {
|
||
|
|
return fixer.removeRange(range);
|
||
|
|
}
|
||
|
|
},
|
||
|
|
{
|
||
|
|
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 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) {
|
||
|
|
parseRegExp(node.regex.pattern)
|
||
|
|
|
||
|
|
/*
|
||
|
|
* 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.
|
||
|
|
*/
|
||
|
|
.filter(charInfo => !(charInfo.text === "-" && charInfo.inCharClass && !charInfo.startsCharClass && !charInfo.endsCharClass))
|
||
|
|
|
||
|
|
/*
|
||
|
|
* 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.
|
||
|
|
*/
|
||
|
|
.filter(charInfo => !(charInfo.text === "^" && charInfo.startsCharClass))
|
||
|
|
|
||
|
|
// Filter out characters that aren't escaped.
|
||
|
|
.filter(charInfo => charInfo.escaped)
|
||
|
|
|
||
|
|
// Filter out characters that are valid to escape, based on their position in the regular expression.
|
||
|
|
.filter(charInfo => !(charInfo.inCharClass ? REGEX_GENERAL_ESCAPES : REGEX_NON_CHARCLASS_ESCAPES).has(charInfo.text))
|
||
|
|
|
||
|
|
// Report all the remaining characters.
|
||
|
|
.forEach(charInfo => report(node, charInfo.index, charInfo.text));
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
return {
|
||
|
|
Literal: check,
|
||
|
|
TemplateElement: check
|
||
|
|
};
|
||
|
|
}
|
||
|
|
};
|