Cannot reference this.$f7.methods inside vue component

the this.$f7.methods property is an Observer which looks useless.
How can I access the root component (app) methods?

Even if it is Observer, it doesn’t mean it won’t work. It should work

Thank you Vladimir for being in touch.
Here what this.$f7.methods is

{__ob__: Observer}
__ob__: Observer {value: {…}, dep: Dep, vmCount: 0}
__proto__: Object

but my app.vue is initialized as

export default{
   methods : {
       mounted() ...,
       doLogin() ...

If it is a root Vue component methods, then in Vue they are under this.$root object