length of an object in javascript

JavaScript
var person={
    "first_name":"Harry",
    "last_name":"Potter",
    "age":14
};
var personSize = Object.keys(person).length; //gets number of properties (3) Object.size = function(obj) {
    var size = 0, key;
    for (key in obj) {
        if (obj.hasOwnProperty(key)) size++;
    }
    return size;
};

// Get the size of an object
var size = Object.size(myObj);//length of this object is 4
let object = {
  'A':{
    '10':['a','b','c']
  }, 
  'B':{
    '20':['a','b','c']
  }, 
  'C':{
    '30':['a','b','c']
  }, 
  'D':{
    '40':['a','b','c']
  },   
}

//Get the keys of the object (A,B,C,D) and print how many there are
Object.keys().length
> prints: 4

Source

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