Download after request finish - vue-json-excel

I am using the vue-json-excel library which helps me to download data from a json to excel.

where in the vue view I have:

<div class="column is-narrow" @click="btDispatch">
    <json-excel
      class   = "button is-primary"
     :data   = "routes"
     :fields = "json_fields_routes"
     :name    = "`descarga-rutas.xls`">
    <span class="icon"><i class="fa fa-download"></i></span><span>Descargar entregas</span>
   </json-excel>

Where :data = "routes" is the json to download: and this is the data at the bottom:

data () {
  return {
     json_fields_routes: {
       ruta_id: 'id',
       fecha: 'date',
       estado_codigo: 'route_state',
       estado: 'estado',
       vehículo: 'vehicle',
       conductor_codigo: 'worker.id',
       conductor_nombre: 'worker.name',
       hora_inicio: 'date_start_web',
       hora_fin: 'date_end_web',
       entregas: 'dispatches_count',
       pendientes: 'pendientes',
       entregados: 'entregados',
       parciales: 'parciales',
       no_entregados: 'noEntregados',
     },
     json_meta: [
      [
        {
          key: 'charset',
          value: 'utf-8',
        },
      ],
    ],
  }
}

According to the documentation I must do this to be able to download the excel and it works correctly. The problem I have is that this downloads when there is existing data but I am working with data that comes from the server and previously I loaded it in load() but sometimes it tends to see a lot of data and it usually takes a while to want to enter the section of download, so I prefer to use a download button and then just load the data and download. So far I have:

methods: {
  btRoute() {
        this.axios.post('/routesdownload/filter_route/', this.params)
            .then((response) => {
              this.routes = response.data.results;
              for (let i = 0; i < this.routes.length; i++) {
                this.routes[i].pendientes = this.filterByStatus(this.routes[i].dispatches, 1);
                this.routes[i].entregados = this.filterByStatus(this.routes[i].dispatches, 2);
                this.routes[i].parciales = this.filterByStatus(this.routes[i].dispatches, 3);
                this.routes[i].noEntregados = this.filterByStatus(this.routes[i].dispatches, 4);
                this.routes[i].date = moment(this.routes[i].date).format('YYYY/MM/DD');
                if (this.routes[i].date_start_web && this.routes[i].date_end_web != null) {
                  this.routes[i].date_start_web
                  = moment(this.routes[i].date_start_web).format('YYYY/MM/DD HH:mm:ss');
                  this.routes[i].date_end_web
                  = moment(this.routes[i].date_end_web).format('YYYY/MM/DD HH:mm:ss');
                } else {
                  this.routes[i].date_start_web = '-';
                  this.routes[i].date_end_web = '-';
                }
                if (this.routes[i].route_state === 1) {
                  this.routes[i].estado = 'Borrador';
                } else if (this.routes[i].route_state === 2) {
                  this.routes[i].estado = 'Publicado';
                } else if (this.routes[i].route_state === 3) {
                  this.routes[i].estado = 'Iniciado';
                } else {
                  this.routes[i].estado = 'Terminado';
                }
              }
            });
      },
}

But this just fetches the data and the weapon as needed but how could I after finishing the request, call the function that downloads with this library? I could do it with a callback or a promise but how do I call that download function.