Gtk.FileChooser.prototype.set_preview_widget

function set_preview_widget(preview_widget:Gtk.Widget):void {
    // Gjs wrapper for gtk_file_chooser_set_preview_widget()
}

Sets an application-supplied widget to use to display a custom preview of the currently selected file. To implement a preview, after setting the preview widget, you connect to the Gtk.update-preview signal, and call Gtk.FileChooser.prototype.get_preview_filename or Gtk.FileChooser.prototype.get_preview_uri on each change. If you can display a preview of the new file, update your widget and set the preview active using Gtk.set_preview_widget_active. Otherwise, set the preview inactive.

When there is no application-supplied preview widget, or the application-supplied preview widget is not active, the file chooser may display an internally generated preview of the current file or it may display no preview at all.

Since 2.4