Reselect selector example for post object

selector-example1.ts

// Code goes here
const {createSelector} = Reselect ;

const state = {
  posts: [
     {
       title:'testing',
       id: 1
     },
     {
       title:'playing',
       id: 2
     },
     {
       title: 'dancing',
       id: 3
     },
     {
       title: 'singing',
       id: 4
     }
    
    ],
    selectedPostIds : [
      1,
      3,
      4
      ]
};

// selector
const getPosts = state => state.posts;
const getSelectedPostIds = state => state.selectedPostIds;

console.log( 'all posts' , getPosts(state) ); 
console.log( 'selected post ids' , getSelectedPostIds(state) ); 

// reselect selector
const getSelectedPosts = createSelector(
  getPosts,
  getSelectedPostIds,
  (posts, ids) => 
    posts.filter(p=>ids.indexOf(p.id)>-1)
  );
  
  console.log( 'selected posts' , getSelectedPosts(state));