JSFiddle - React, Tailwind, and code Playground

JavaScript

var friends = {
    bill: {
        firstName: 'Biill',
        lastName: 'Gates',
        number: '1-111',
        address: ['Microsoft', 'Kalifornia']
    },
    steve: {
        firstName: 'Steive',
        lastName: 'Jobs',
        number: '2-222',
        address: ['Apple', 'New-York']
    }
};
var list = function(){
    for (firstName in friends){
        console.log(firstName);
    }
};