back.js

router.get("/", auth.authenticate(), middle.getroles, middle.roles(["user"]), function (req, res){
  if(req.query.path){
    res.sendFile("/mnt/vol0/storage"+req.query.path, {}, function (err) { //I know this is dangerous
      if (err) {
        console.log(err);
        res.status(500).json(err);
      }
      else {
        console.log('Sent:', req.query.path);
      }
    })
  }else{
    res.sendStatus(404);
  }
});

front.js

            download: function(file){
                console.log("Downloading...", file.file);
                this.$http.get("/api/ftp", {
                    headers: {
                      "Content-Type": "application/json",
                      "Authorization": `JWT ${this.$router.app.token}`
                    },
                    params: {
                        path: file.full
                    }
                })
              .then((data) => {
                    console.log(data);
                    window.debug = data;
                    let bfile = new Blob([data.data], {type: data.headers["Content-Type"]});
                    window.saveAs(bfile, file.file);
              })
              .catch((err)=>{console.error(err);});
            }

//Vue-resource https://github.com/vuejs/vue-resource/blob/master/docs/http.md

window.saveAs: https://github.com/eligrey/FileSaver.js/ from CDN