how to commit inputs v-model, recived by v-for directive

Question

I don't know how to commit v-models of inputs after used v-for directive. Can someone tell me ho to pass index to computed or any other way of proper way of commiting in this situation.

here is example: template part

<q-list v-for="(book, index) in $store.state.documents[docIndex].contents[contentIndex].books" :key='index'>
 <q-input v-model="booksTitle"/>
</q-list>

script part

export default defineComponent({
    name: 'ProductComponent',
    props:{
      docIndex:{
        type: Number
      },
      contentIndex:{
        type: Number
      },
    },
    setup(props) {
    const store = useStore()

      let booksTitle = computed({
      get: () => {
       if(store.state.documents && props.docIndex && props.contentIndex)
       {return store.state.documents[props.docIndex].contents[props.contentIndex].books[index].tile}//here is the tricki part
       else{
        return 'no document'
      }},
      set:( val ) => { 
       store.commit('ST_TITLE_MUTATION', {val , props, index})//here is also tricki part
      }
    })    

    return { 
        booksTitle
    };
  },
})