Javascript – Slug

A slug is a way to represent a title with a limited charset (only lowercase letter and dash) to be inserted in the url. Even if it is a common function there is no good enough implentation when you Google for it.

Here are the features I needed:

  • No multiple dashes. ---- is converted to -
  • No wrapping dashes. -title- is converted to title
  • Basic support for internationalization. Coût d'éclat is converted to cout-d-eclat Don't look at the spelling mistake!
  • Basic support for common signs. 13$ & 12€ is converted to 13-dollar-and-12-euro


You can try the demo and see if it fits your needs.


var keys = keys || function (o) { var a = []; for (var k in o) a.push(k); return a; };
var slug = function (string) {
//  var accents = "àáäâèéëêìíïîòóöôùúüûñç";
  var accents = "\u00e0\u00e1\u00e4\u00e2\u00e8"
    + "\u00e9\u00eb\u00ea\u00ec\u00ed\u00ef"
    + "\u00ee\u00f2\u00f3\u00f6\u00f4\u00f9"
    + "\u00fa\u00fc\u00fb\u00f1\u00e7";
  var without = "aaaaeeeeiiiioooouuuunc";
  var map = {'@': ' at ', '\u20ac': ' euro ', 
    '$': ' dollar ', '\u00a5': ' yen ',
    '\u0026': ' and ', '\u00e6': 'ae', '\u0153': 'oe'};
  return string
    // Handle uppercase characters
    // Handle accentuated characters
      new RegExp('[' + accents + ']', 'g'),
      function (c) { return without.charAt(accents.indexOf(c)); })
    // Handle special characters
      new RegExp('[' + keys(map).join('') + ']', 'g'),
      function (c) { return map[c]; })
    // Dash special characters
    .replace(/[^a-z0-9]/g, '-')
    // Compress multiple dash
    .replace(/-+/g, '-')
    // Trim dashes
    .replace(/^-|-$/g, '');


If you are bored, here is a little exercise for you. Can you find a and b such as

a >= b && a < = b
// true
a == b
// false
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