What is cssesc?
The cssesc npm package is a utility for escaping strings to be used in CSS selectors and strings. It provides a way to generate CSS-compatible strings, ensuring that any input can be safely used in CSS contexts without causing syntax errors or unintended behaviors.
What are cssesc's main functionalities?
Escaping strings for CSS identifiers
This feature allows you to escape strings to be safely used as CSS identifiers, such as class names or IDs. The code sample demonstrates escaping a string that starts with a digit, which would normally not be valid as a CSS identifier without escaping.
cssesc('123abc'); // Returns '\31 23abc'
Escaping strings for CSS strings
This feature is used for escaping strings to be included in CSS string values. The code sample shows how to escape quotes within a string, making it safe to use within CSS string contexts, such as in the content property.
cssesc('"Hello, world!"', {isIdentifier: false}); // Returns '"\"Hello, world!\""'
Customizing escape options
This feature allows for customization of the escaping behavior, such as wrapping the output in quotes. The code sample demonstrates how to automatically wrap the escaped string in quotes, which is useful for generating CSS string values.
cssesc('Hello, world!', {wrap: true}); // Returns '"Hello, world!"'
Other packages similar to cssesc
he
The 'he' package is an HTML entity encoder/decoder. While it focuses on HTML rather than CSS, it serves a similar purpose in providing safe strings for web contexts. Compared to cssesc, 'he' is more suited for HTML content encoding and decoding rather than CSS-specific escaping.
escape-html
This package provides a simple method to escape HTML characters. Like cssesc, it ensures that strings can be safely inserted into web contexts, but it is specifically tailored for HTML rather than CSS. It lacks the CSS-specific options and escaping rules provided by cssesc.
cssesc

A JavaScript library for escaping CSS strings and identifiers while generating the shortest possible ASCII-only output.
This is a JavaScript library for escaping text for use in CSS strings or identifiers while generating the shortest possible valid ASCII-only output. Here’s an online demo.
A polyfill for the CSSOM CSS.escape()
method is available in a separate repository. (In comparison, cssesc is much more powerful.)
Feel free to fork if you see possible improvements!
Installation
Via npm:
npm install cssesc
In a browser:
<script src="cssesc.js"></script>
In Node.js:
const cssesc = require('cssesc');
In Ruby using the ruby-cssesc
wrapper gem:
gem install ruby-cssesc
require 'ruby-cssesc'
CSSEsc.escape('I ♥ Ruby', is_identifier: true)
In Sass using sassy-escape
:
gem install sassy-escape
body {
content: escape('I ♥ Sass', $is-identifier: true);
}
API
cssesc(value, options)
This function takes a value and returns an escaped version of the value where any characters that are not printable ASCII symbols are escaped using the shortest possible (but valid) escape sequences for use in CSS strings or identifiers.
cssesc('Ich ♥ Bücher');
cssesc('foo 𝌆 bar');
By default, cssesc
returns a string that can be used as part of a CSS string. If the target is a CSS identifier rather than a CSS string, use the isIdentifier: true
setting (see below).
The optional options
argument accepts an object with the following options:
isIdentifier
The default value for the isIdentifier
option is false
. This means that the input text will be escaped for use in a CSS string literal. If you want to use the result as a CSS identifier instead (in a selector, for example), set this option to true
.
cssesc('123a2b');
cssesc('123a2b', {
'isIdentifier': true
});
quotes
The default value for the quotes
option is 'single'
. This means that any occurences of '
in the input text will be escaped as \'
, so that the output can be used in a CSS string literal wrapped in single quotes.
cssesc('Lorem ipsum "dolor" sit \'amet\' etc.');
cssesc('Lorem ipsum "dolor" sit \'amet\' etc.', {
'quotes': 'single'
});
If you want to use the output as part of a CSS string literal wrapped in double quotes, set the quotes
option to 'double'
.
cssesc('Lorem ipsum "dolor" sit \'amet\' etc.', {
'quotes': 'double'
});
wrap
The wrap
option takes a boolean value (true
or false
), and defaults to false
(disabled). When enabled, the output will be a valid CSS string literal wrapped in quotes. The type of quotes can be specified through the quotes
setting.
cssesc('Lorem ipsum "dolor" sit \'amet\' etc.', {
'quotes': 'single',
'wrap': true
});
cssesc('Lorem ipsum "dolor" sit \'amet\' etc.', {
'quotes': 'double',
'wrap': true
});
escapeEverything
The escapeEverything
option takes a boolean value (true
or false
), and defaults to false
(disabled). When enabled, all the symbols in the output will be escaped, even printable ASCII symbols.
cssesc('lolwat"foo\'bar', {
'escapeEverything': true
});
Overriding the default options globally
The global default settings can be overridden by modifying the css.options
object. This saves you from passing in an options
object for every call to encode
if you want to use the non-default setting.
cssesc.options.escapeEverything;
cssesc.options.escapeEverything = true;
cssesc('foo © bar ≠ baz 𝌆 qux');
cssesc.version
A string representing the semantic version number.
Using the cssesc
binary
To use the cssesc
binary in your shell, simply install cssesc globally using npm:
npm install -g cssesc
After that you will be able to escape text for use in CSS strings or identifiers from the command line:
$ cssesc 'föo ♥ bår 𝌆 baz'
f\F6o \2665 b\E5r \1D306 baz
If the output needs to be a CSS identifier rather than part of a string literal, use the -i
/--identifier
option:
$ cssesc --identifier 'föo ♥ bår 𝌆 baz'
f\F6o\ \2665\ b\E5r\ \1D306\ baz
See cssesc --help
for the full list of options.
Support
This library supports Node.js v4+ only. For a version that supports browser and environments out-of-the-box, see v0.1.0.
Author
License
This library is available under the MIT license.