Length of a JavaScript object

Question

I have a JavaScript object. Is there a built-in or accepted best practice way to get the length of this object?

const myObject = new Object();
myObject["         


        

Answer 1

A nice way to achieve this (Internet Explorer 9+ only) is to define a magic getter on the length property:

Object.defineProperty(Object.prototype, "length", {
    get: function () {
        return Object.keys(this).length;
    }
});

And you can just use it like so:

var myObj = { 'key': 'value' };
myObj.length;

It would give 1.