Is this an instance of 'deep copy' for a JavaScript object?

Question

I have the following set up: fetch some documents from Mongo. If there is a 'gap' in the dates then compute dates and insert missing rows. An additional requirement is that if the most recent user entry is "Yes", then I should copy the object into each of the inserted rows, i.e. pre-fill some data. Here's a simple example of the object:

{
  "section1": {},
  "section2": {},
  "section3": {},
  "section4": {
    "question1": "Y",
    "question2": "N",
    "question3": "true",
    "question4": "false",
    "question5": "05/15/2017"
  },
  "section5": {}
}

So, if I understand things correctly, I can't simply do something like:

if(oldObj.section4.question1==="Y"){
    newObj.section4 = oldObj.section4; //copy the enter sub object 
}

JS copies 'by reference'. I need to deep copy oldObj.section4 entirely. It doesn't look like there is an simple way to do this. NPM has a deep copy module that I might take a look at. Any advice would be appreciated. Is this the correct approach?