Circular references

blog.js

const posts = {
  'first': {
    title: 'first'
  },
  'second': {
    title: 'second'
  },
  'third': {
    title: 'third'
  }
};

posts.first.next = posts.second;
posts.second.previous = posts.first;
posts.second.next = posts.third;
posts.third.previous = posts.second;

console.log(posts);
/*
posts: {
  first: 
   { title: 'first',
     next: { title: 'second', previous: [Circular], next: [Object] }
   },
  second: 
   { title: 'second',
     previous: { title: 'first', next: [Circular] },
     next: { title: 'third', previous: [Circular] }
   },
  third: 
   { title: 'third',
     previous: { title: 'second', previous: [Object], next: [Circular] }
   }
}
*/