less

What is less?

The 'less' npm package is a pre-processor for CSS, which extends the capabilities of CSS with dynamic behavior such as variables, mixins, operations, and functions. It allows developers to write CSS in a more maintainable and extendable way.

What are less's main functionalities?

Variables

Variables allow you to specify widely used values in a single place, and then reuse them throughout the stylesheet, making your CSS more maintainable.

@primary-color: #4D9FEC;

a {
  color: @primary-color;
}

Mixins

Mixins allow you to embed all the properties of a class into another class by simply including the class name as one of its properties. It's like variables, but for whole classes.

.bordered {
  border-top: dotted 1px black;
  border-bottom: solid 2px black;
}

#menu a {
  .bordered;
}

Nested Rules

Nested rules make it possible to nest selectors inside other selectors. This makes the structure of your CSS mirror the structure of your HTML.

#header {
  color: black;
  .navigation {
    font-size: 12px;
  }
  .logo {
    width: 300px;
  }
}

Functions & Operations

Functions and operations let you manipulate numbers and colors, doing math with them and applying functions to achieve dynamic results.

@base: 5%;

.padding {
  padding: @base * 2;
}

Other packages similar to less

sass

Sass (Syntactically Awesome Stylesheets) is a mature, stable, and powerful professional grade CSS extension language. It provides similar features to Less, such as variables, mixins, and nested rules. Sass has two syntaxes: the original 'indent' syntax that is similar to Haml and the newer 'SCSS' that uses braces like CSS. It's one of the most popular CSS preprocessors.

stylus

Stylus is a preprocessor that offers a mix of features from both Sass and Less, as well as some additional unique features. It has a more flexible syntax that can be written with or without braces, colons, and semicolons. Stylus provides powerful and efficient stylesheet writing capabilities.

postcss

PostCSS is a tool for transforming CSS with JavaScript plugins. These plugins can lint your CSS, support variables and mixins, transpile future CSS syntax, inline images, and more. PostCSS is different from preprocessors like Sass and Less in that it's modular and can be configured to perform a wide variety of tasks.

README

less.js

about

less.js is the next evolution of LESS, eventually, it will become LESS 2.0. less.js is a complete rewrite of LESS in JavaScript, and will be able to run directly in the browser, as well as on the server, with node.js.

where do I get it?

Go to the Downloads section, and get the latest version:

http://github.com/cloudhead/less.js/downloads

synopsis

in node.js

var less = require('less');

less.render(".class { width: 10px * 2 }", function (e, css) {
    sys.puts(css); // .class { width: 20px }
});

via the command-line (requires node)

bin/lessc style.less

in the browser

First, run make less in the command line. It will the build the less.js file in dist/. Then, you can use it as such:

<link rel="stylesheet/less" href="main.less" type="text/css">
<script src="less.js"></script>

To build a minified version, run make min

installation

In node:

$ npm install less