how to get object field name in javascript code example

Example 1: javascript list object properties

var person={"first_name":"Bill","last_name":"Jenner"}
//get the person object properties with:
var keys = Object.keys(person); //keys = ["first_name","last_name"]

Example 2: get object name javascript

var a = {
    name:'a',
    'light': 'good',
    'dark' : {
         name: 'dark',
        'black': 'bad',
        'gray' : 'not so bad'
    }
}

// This way you can do

console.log(a.name,a.dark.name);