beforeMount hook in Vue.js framework

life-cycle-hooks.js

export default {
	beforeMount
}

function beforeMount(){
	/*
		This is one of the most important functions for the hacker-news app
	*/
	const 
		vm = this,
		{ state, dispatch } 		
			= vm.$store,
		itemId 									
			= vm.$route.params.itemId,
		fetchItems							
			= ids => dispatch('FETCH_ITEMS', { ids }),
		getFetchedItem		 			
			= () => Promise.resolve(state.items[itemId]),
		getAllCommentsForItem		
			= item => item.kids ? fetchItems(item.kids).then(() => fetchKidComments(item.kids)) : null,
		fetchKidComments				
			= kids => Promise.all(kids.map(kid => getAllCommentsForItem(state.items[kid])))
	
	fetchItems([ itemId ])
		.then(getFetchedItem)
		.then(getAllCommentsForItem)
		.then(() => vm.loading = false)
}