JS - To Slug

toslug.js

String.prototype.toSlug = function (replaceWith) {
    replaceWith = replaceWith || '-';
    var str = this.replace(/^\s+|\s+$/g, ''); // trim
    str = str.toLowerCase();

    // remove accents, swap ñ for n, etc
    var from = "ãàáäâẽèéëêìíïîõòóöôùúüûñç·/_,:;";
    var to   = "aaaaaeeeeeiiiiooooouuuunc------";
    for (var i=0, l=from.length ; i<l ; i++) {
        str = str.replace(new RegExp(from.charAt(i), 'g'), to.charAt(i));
    }

    str = str.replace(/[^a-z0-9 -]/g, '') // remove invalid chars
            .replace(/\s+/g, replaceWith) // collapse whitespace and replace by -
            .replace(/-+/g, replaceWith); // collapse dashes

    return str;
};