How to fix JSON.stringify returning an empty object

I write a lot of Javascript and ran into a pretty awful bug today that took me 3 hours to figure out. In the hopes of this saving someone else an equal amount of time I am writing about how I fixed it here.

I am developing a chrome extension that makes the internet private again. No tracking, no bad actors, etc. I have written a few libraries to use for the project for simple things like auth with google and http requests.

I usually use things like axios but wanted to roll my own and interface with raw XML HTTPRequests. Last night I was running out the door but made a few code changes I didn't quite think through. Bad move.

I have 2 methods that ended up being the way to fix.

In my auth.js method I was passed an object from Google like so:

{ "email": "kameronkales", "id": 1298179834}

In my history.js I was creating what I thought was an object (but was really an array).

I created the array like so:

var i;
var example_list = []
for (i = 0; i < bad_list.length; i++) {
var clean = bad_list[i]
    example_list.push(clean)
}

This was not doing what I thought.

When I console.logged the data from example_list I was getting:

{ 
    0: "https://google.com",
    1: "https://google.com",
    2: "https://google.com
}

Which, now seems obviously wrong. But I didn't realize until looking at the data.

JSON.stringify doesn't know what to do with those int fields. So, it drops them.

When I would run

JSON.stringify(example_list)

I would be returned this:

[]

And it drove me insane! Because I knew the array had fields in it. But I wasn't paying enough attention (I know, I know. Won't do that again.)

I ended up being able to fix this by the following:

var urls = {}   <= an actual object

.....HTTP requests to get the data I wanted 

urls['data'] = data

This now returns a nice object that looks like the following:

{
    'data': 'https://google.com',
    'data': 'https://google.com',
    'data' : 'https://google.com'
}

There are a ton of ways to clean this up and format better. But I spent way too long trying to figure out why this simple method didn't work the way I wanted it too.

Hopefully this saves you some time.