---
title: "Differences Between Null and Undefined in Node.js"
date: 2023-05-29T14:35:44.000Z
author: Z.SHINCHVEN
tags: [undefined, null, Node.js]
canonical: https://atlassc.net/2023/05/29/differences-between-null-and-undefined-in-node-js
---
In Node.js, `null` and `undefined` are both used to represent the absence of a value, but they have different meanings.

`undefined` means that a variable has been declared but has not been assigned a value. It is also the default return value of a function that does not return anything.

`null`, on the other hand, is an assignment value that represents no value or no object. It is often used to indicate that a variable should have no value or that a function should return no value.

In general, it is recommended to use `undefined` when a variable has not been assigned a value, and `null` when you want to explicitly indicate that a variable has no value.

In Node.js, you can check if a variable is `undefined` or `null` using the strict equality operator (`===`). Here's an example:

```javascript
if (myVar === undefined) {
  // myVar is undefined
}

if (myVar === null) {
  // myVar is null
}
```

Alternatively, you can use the `typeof` operator to check if a variable is `undefined`. Here's an example:

```javascript
if (typeof myVar === 'undefined') {
  // myVar is undefined
}
```

Note that `typeof null` returns `'object'`, so you cannot use `typeof` to check if a variable is `null`.

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