code: function mount(data) {
    var promises = [];
    this.each(function() {
      var view = select(this).view();
      if (view) promises.push(mountElement(this, view, data));
      else warn("Cannot mount, no view object available to mount to");
    });
    return Promise.all(promises);
  }
docs: mount function on a d3 selection Use this function to mount the selection This method returns nothing or a promise