NodeJS: Using console.dir() over console.log() with deeply nested objects.

console.dir() seems rather redundant. At least with console.log(), you can add as many arguments as you want, but with console.dir(), you can only log one.

Despite that, for debugging, I'll be using console.dir() more in future. Here's why?

Let's take a deeply nested object.

let hello = {
    world: true,
    nested: {
        obj: {
            with: "some text",
            and: {
                numbers: {
                    count: [1,2,3,4,5,6,7,8,9,10],
                    symbol: Symbol("1"),
                }
            }
        }
    }
}

console.log() to debug

Now, if you do a pure console.log:

You'll be missing some of the properties that are past a certain depth.
The output is on a single line and not structured in an easily readable way.

# console.log(hello)
{ world: true, nested: { obj: { with: 'some text', and: [Object] } } }

console.log() to get the whole object

How I'd normally get around expanding that [Object] is using trusty old JSON.stringify. And voila 🎉! We have the entire object displayed.

# console.log(JSON.stringify(hello))
{"world":true,"nested":{"obj":{"with":"some text","and":{"numbers":{"count":[1,2,3,4,5,6,7,8,9,10]}}}}}

console.log() but pretty

While we could see the entire object before, it's not easy to read. We can fix that by using the JSON.stringify formatting argument:

# console.log(JSON.stringify(hello, null, 2))
{
  "world": true,
  "nested": {
    "obj": {
      "with": "some text",
      "and": {
        "numbers": {
          "count": [
            1,
            2,
            3,
            4,
            5,
            6,
            7,
            8,
            9,
            10
          ]
        }
      }
    }
  }
}

And this is much better, but it still isn't great. Look at that array! That's equally impractical.

console.dir() for better readability

Now, compare all that hard work with console.dir. You have to add the depth you want to be printed to get the entire object out.

console.dir(hello, { depth: 99 })

And it looks like this:

{
  world: true,
  nested: {
    obj: {
      with: 'some text',
      and: {
        numbers: {
          count: [
            1, 2, 3, 4,  5,
            6, 7, 8, 9, 10
          ],
          symbol: Symbol(1)
        }
      }
    }
  }
}

It has nice terminal colours because it's not JSON. It's Javascript! It benefits from the conciseness of javascript and is more compact and yet more readable.

Getting a little more out console.dir()

There are three options you can pass into the formatting argument with console.dir(). We've already covered depth so we'll skip that.


console.dir(hello, {
    showHidden: true,
    depth: 99,
    colors: true
})

showHidden allows you to see Javascript annotations such as the length of an array.

{
  ...
        count: [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, [length]: 10 ],
  ...
}

colors by default is true (for me) in the terminal, but you can turn it off if you want. I find the colouring helpful though:

There's nothing more to say really. As I'm reading the Nodejs and finding little gems to make life a little easier. Maybe it's helpful to you.