What is the most efficient way to clone a JavaScript object?

What is the most efficient way to clone a JavaScript object? I've seen:

How do I count a JavaScript object"s attributes?

Suppose I have the following object in JavaScript:

var object = {

  "key1": "value1",

  "key2": "value2",

  "key3": "value3"

};

How to get json data from a file (jQuery)

Just cant figure it out. I have a large object stored as a JSON file and I want to access it once and use it multiple times:

JavaScript "this" confusion

This is probably pretty easy, yet I am confused, so maybe I might still learn something more today. I am trying to do the following:

Does using method chaining in PHP cause any problems with resources or memory?

I'm talking about methods like this: