inspect.js

var Person = function(_name){
  this.name = _name;
  this.friends = [];
};

var obj = new Person("ore");
obj.friends.push(new Person("satou"));


obj.friends[0].friends.push(new Person("yamada"));
obj.friends[0].friends.push(new Person("ueda"));

var util = require('util');

console.log(util.inspect(obj,false,null));
/*
  { name: 'ore',
    friends:
     [ { name: 'satou',
         friends:
          [ { name: 'yamada', friends: [] },
            { name: 'ueda', friends: [] } ] } ] }
 */

Thank you so much 👍