Create slug from string in Javascript

slugify.js

function string_to_slug (str) {
    str = str.replace(/^\s+|\s+$/g, ''); // trim
    str = str.toLowerCase();
  
    // remove accents, swap ñ for n, etc
    var from = "àáäâèéëêìíïîòóöôùúüûñç·/_,:;";
    var to   = "aaaaeeeeiiiioooouuuunc------";
    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, '-') // collapse whitespace and replace by -
        .replace(/-+/g, '-'); // collapse dashes

    return str;
}

Look seem that does not work for "đ" char

@auvansang
You are right, "đ" can not be normalized, because it's not the combination of a letter with an accent, it's a letter by itself.
Check this:
https://stackoverflow.com/questions/2362810/why-doesnt-%C4%90-get-flattened-to-d-when-removing-accents-diacritics