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/**
* @fileoverview Look for useless escapes in strings and regexes
* @author Onur Temizkan
*/
"use strict";
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
var VALID_STRING_ESCAPES = [
"\\",
"n",
"r",
"v",
"t",
"b",
"f",
"u",
"x",
"\n",
"\r"
];
var VALID_REGEX_ESCAPES = [
"\\",
".",
"-",
"^",
"$",
"*",
"+",
"?",
"{",
"}",
"[",
"]",
"|",
"(",
")",
"b",
"B",
"c",
"d",
"D",
"f",
"n",
"r",
"s",
"S",
"t",
"v",
"w",
"W",
"x",
"u"
];
module.exports = {
meta: {
docs: {
description: "disallow unnecessary escape characters",
category: "Best Practices",
recommended: false
},
schema: []
},
create: function(context) {
/**
* Checks if the escape character in given slice is unnecessary.
*
* @private
* @param {string[]} escapes - list of valid escapes
* @param {ASTNode} node - node to validate.
* @param {string} elm - string slice to validate.
* @returns {void}
*/
function validate(escapes, node, elm) {
var escapeNotFound = escapes.indexOf(elm[0][1]) === -1;
var isQuoteEscape = elm[0][1] === node.raw[0];
if (escapeNotFound && !isQuoteEscape) {
context.report({
node: node,
loc: {
line: node.loc.start.line,
column: node.loc.start.column + elm.index
},
message: "Unnecessary escape character: " + elm[0]
});
}
}
/**
* Checks if a node has an escape.
*
* @param {ASTNode} node - node to check.
* @returns {void}
*/
function check(node) {
var nodeEscapes, match;
var pattern = /\\[^\d]/g;
if (typeof node.value === "string") {
// JSXAttribute doesn't have any escape sequence: https://facebook.github.io/jsx/
if (node.parent.type === "JSXAttribute") {
return;
}
nodeEscapes = VALID_STRING_ESCAPES;
} else if (node.regex) {
nodeEscapes = VALID_REGEX_ESCAPES;
} else {
return;
}
while ((match = pattern.exec(node.raw))) {
validate(nodeEscapes, node, match);
}
}
return {
Literal: check
};
}
};
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