How to print values of a object in JavaScript? [duplicate]

Question

I have an object

var friends = {
    bill: {
       firstName: "A",
       lastName: "C",
       number: "999",
    },
};

How can I print the values of the object friends using a for...loop?

Answer 1

var friends = {
    bill:
    {
        firstName: "A",
        lastName: "C",        
        number: "999",
    },
    print: function () {
        for (var p in this.bill)
            console.log(p + ' ' + this.bill[p]);
    }
};

This code will print, is that what you need?

friends.print();

Answer 2

I'm going to make a suggestion that might make your coding a little easier. Instead of using an object to contain a list of friends, use an array instead. An array is a list after all, and Javascript comes with some really useful array functions that can help you in the long run.

var friends = [
  {
   name: 'Bill Z',
   firstName: "Bill",
   lastName: "X",
   number: "999",
  },
  {
   name: 'Sam Y',
   firstName: "Sam",
   lastName: "Y",
   number: "999",
  }    
];

To get the list of friends you might use a couple of loops; one to loop over the list of objects, and one to loop over the properties of each object:

function listFriends() {
  for (var i = 0, l = friends.length; i < l; i++) {
    for (var p in friends[i]) {
        console.log(p + ': ' + friends[i][p]);
    }
  }
}

Or to get HTML out:

function listFriends() {
  var html = '';
  for (var i = 0, l = friends.length; i < l; i++) {
    html += '<b>' + friends[i].firstName + '</b><br/>';
    for (var p in friends[i]) {
        html += p.toUpperCase() + ': ' + friends[i][p] + '<br/>';
    }
  }
  return html;
}

You might also like to access the list of friends to find one in particular. In this example I use filter.

function getFriend(prop, value) {
  return friends.filter(function (obj) {
    return obj[prop] === value;
  });
}

console.log(getFriend('firstName', 'Sam')) // { name="Sam Y", firstName="Sam", lastName="Y"}

Fiddle.

Hopefully you'll find some of this useful.

Answer 3

If you'd like to print only the members of within friends.bill, you might want to use a for..in loop, for example:

for(var p in friends.bill) 
    console.log(p + ": " + friends.bill[p])

Which will print this in the console:

firstName: A VM579:3
lastName: C VM579:3
number: 999