Custom javascript function in less

less-custom.js

/**
 * node less-custom.js
 * --> .class{width:2;height:olleh}
 */

var less = require('less.js/lib/less');

less.tree.functions.reverse = function (args) {
  return new(less.tree.Anonymous)(new(less.tree.Anonymous)(args.value.split("").reverse().join("")));
}

var parser = new(less.Parser)();
parser.parse('.class { width: (1 + 1); height: reverse("hello") }', function (e, tree) {
  var css = tree.toCSS({ compress: true }); // Minify CSS output
  console.log(css);
});