index.js

export default (url) => {
       let dropbox_regex = /(http(s)*:\/\/)*(www\.)*(dropbox.com)/;
       let drive_regex = /(http(s)*:\/\/)*(www\.)*(drive.google.com\/file\/d\/)/;

       let drive_direct_url_regex = /^(https:\/\/drive.google.com\/uc\?id=)/;
       let dropbox_direct_url_regex = /^(https:\/\/dl.dropbox.com)/;

       // if it's already a direct url
       if (
              url.match(drive_direct_url_regex) ||
              url.match(dropbox_direct_url_regex)
       ) {
              return url;
       }

       // converting dropbox url 
       if (url.match(dropbox_regex)) {
              return url.replace(/(http(s)*:\/\/)*(www\.)*/, "https://dl.");
       }

       // converting google drive url 
       if (url.match(drive_regex)) {
              return `https://drive.google.com/uc?id=${url
                     .replace(drive_regex, "")
                     .match(/[\w]*\//)[0]
                     .replace(/\//, "")}`;
       }

       // if Error
       console.error("Wrong URL, not a vlid drobox or google drive url");
       return "Wrong URL, not a vlid drobox or google drive url";
};