How to use in v8

In my v5 svelte project, I had data property used in f7params
below is the code

 let f7params = {
    id: "com.framework7.myapp", // App bundle ID
    name: "My App", // App name
    theme: "md", // Automatic theme detection,

    // App root data
     data: function() {
       return {
         listItems: [],
        settings: { ListHF: {} },

in the v8 I am not able to access, this is undefined