You need better understanding of truthy and falsy values in js... And what is object and what is boolean.

The === equality check is a strong check. If something is truthy is does not necessarily equality-check to true.

Most everything in JavaScript is truthy. The 8 things that are falsy are:

• false
• 0
• ""
• null
• undefined
• -0 (I know, that's underhanded, but -0 is slightly different than 0)
• NaN
• document.all (in the HTML context)

Things that are truthy that occasionally mess people up:
var b = new Boolean(false)
var a = []
var o = {}

and what is weired about it? I think it is super helpful. in the beginning I wrote something like this:

if (obj.prop !== undefined && obj.prop !== null) {
   ...
}

today I do

if (obj.prop) {
   ...
}

I think this is awesome.

and with the new optional chaining operator this get even better.