---
title: "Discussion on \"JS Fundamentals #4 — 🕳️ undefined, null, and NaN\" | Hashnode"
description: "Discussion on \"JS Fundamentals #4 — 🕳️ undefined, null, and NaN\". If you're new to JavaScript (or even experienced), undefined, null, and NaN can feel like three very confusing cousins.They all seem to mean \"nothing\" — but they're very different kinds of nothing.\nLet’s clear it all up, once and for all.\n\n1️⃣ undefi..."
url: "https://hashnode.com/posts/undefined-null-and-nan-in-javascript-explained-clearly/683086503b1b361f70a4d663"
---

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Discussion

# [JS Fundamentals #4 — 🕳️ undefined, null, and NaN](https://pushpesh-js-articles.hashnode.dev/undefined-null-and-nan-in-javascript-explained-clearly?utm_source=hashnode&utm_medium=feed)

If you're new to JavaScript (or even experienced), undefined, null, and NaN can feel like three very confusing cousins.They all seem to mean "nothing" — but they're very different kinds of nothing. Let’s clear it all up, once and for all. 1️⃣ undefi...

May 23, 2025 · 5 min read · pushpesh-js-articles.hashnode.dev  
Updated Dec 4, 2025  
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-   [#javascript](https://hashnode.com/tag/javascript)
-   [#beginnersguide](https://hashnode.com/tag/beginnersguide)
-   [#null](https://hashnode.com/tag/null)
-   [#undefined](https://hashnode.com/tag/undefined)
-   [#nan](https://hashnode.com/tag/nan)

## Written by

[pushpesh kumar](https://hashnode.com/@pushpeshkumar)

@pushpeshkumar · Oslo, Norway

  
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