Escape string for use in Javascript regex [duplicate]
Solution 1:
Short 'n Sweet (Updated 2021)
To escape the RegExp itself:
function escapeRegExp(string) {
return string.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); // $& means the whole matched string
}
To escape a replacement string:
function escapeReplacement(string) {
return string.replace(/\$/g, '$$$$');
}
Example
All escaped RegExp characters:
escapeRegExp("All of these should be escaped: \ ^ $ * + ? . ( ) | { } [ ]");
>>> "All of these should be escaped: \\ \^ \$ \* \+ \? \. \( \) \| \{ \} \[ \] "
Find & replace a string:
var haystack = "I love $x!";
var needle = "$x";
var safeNeedle = escapeRegExp(needle); // "\\$x"
var replacement = "$100 bills"
var safeReplacement = escapeReplacement(replacement); // "$$100 bills"
haystack.replace(
new RegExp(safeNeedle, 'g'),
escapeReplacement(safeReplacement),
);
// "I love $100 bills!"
(NOTE: the above is not the original answer; it was edited to show the one from MDN. This means it does not match what you will find in the code in the below npm, and does not match what is shown in the below long answer. The comments are also now confusing. My recommendation: use the above, or get it from MDN, and ignore the rest of this answer. -Darren,Nov 2019)
Install
Available on npm as escape-string-regexp
npm install --save escape-string-regexp
Note
See MDN: Javascript Guide: Regular Expressions
Other symbols (~`!@# ...) MAY be escaped without consequence, but are not required to be.
.
.
.
.
Test Case: A typical url
escapeRegExp("/path/to/resource.html?search=query");
>>> "\/path\/to\/resource\.html\?search=query"
The Long Answer
If you're going to use the function above at least link to this stack overflow post in your code's documentation so that it doesn't look like crazy hard-to-test voodoo.
var escapeRegExp;
(function () {
// Referring to the table here:
// https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/regexp
// these characters should be escaped
// \ ^ $ * + ? . ( ) | { } [ ]
// These characters only have special meaning inside of brackets
// they do not need to be escaped, but they MAY be escaped
// without any adverse effects (to the best of my knowledge and casual testing)
// : ! , =
// my test "~!@#$%^&*(){}[]`/=?+\|-_;:'\",<.>".match(/[\#]/g)
var specials = [
// order matters for these
"-"
, "["
, "]"
// order doesn't matter for any of these
, "/"
, "{"
, "}"
, "("
, ")"
, "*"
, "+"
, "?"
, "."
, "\\"
, "^"
, "$"
, "|"
]
// I choose to escape every character with '\'
// even though only some strictly require it when inside of []
, regex = RegExp('[' + specials.join('\\') + ']', 'g')
;
escapeRegExp = function (str) {
return str.replace(regex, "\\$&");
};
// test escapeRegExp("/path/to/res?search=this.that")
}());