JavaScript Equality: == vs === Explained

I swear, JavaScript equality is out here trying to gaslight me.

Today, I had a value that printed as 0 in the console… but my if (value == 0) check was somehow skipping.

if(value ==0)

Turns out, it was “0" from some form field.

== said “yeah, same same”, I said “nah fam, not today”.

Then my brain went back to the classics that still hurt:

NaN === NaN -> false 

NaN === NaN → false (who hurt you, NaN?)

typeof null → “object” (bro, we’ve been carrying this L since before I was born)

Get Al-Hussein Abubakar’s stories in your inbox

Join Medium for free to get updates from this writer.

Remember me for faster sign in

and the one that made me close VS Code for 10 minutes: [] ==![] → true 😭

[]==![]-> true

I eventually wrote the post I needed when I was losing my mind over this stuff years ago:

why == is basically playing matchmaker with types,

Why most of us just live on === now,

the one sneaky situation where loose equality is actually cleaner,

and why Object.is() exists for the people who actually care about -0 vs +0 (not me… yet).

Object.is()

If JS equality has ever made you want to throw your laptop into the Gulf of Guinea, tell me your worst one below.

Misery loves company.

I have sat down to write a breakdown with the cursed examples if you want: https://blog.al-husayn.dev/blog/equality-operators

Dropping the link in comments if you’re ready to hate JavaScript a little more today.