# How to convert arguments object to an array in JavaScript

By Atta Ur Rehman Shah (https://attacomsian.com/about). Published Jun 7, 2020, updated Oct 7, 2022. Topics: JavaScript.
Canonical URL: https://attacomsian.com/blog/javascript-convert-arguments-object-to-array

> A quick guide to learning how to convert the arguments object available inside a function to an array in JavaScript. 

The `arguments` object is an array-like [object](https://attacomsian.com/blog/objects-prototypes-classes-javascript#objects) accessible inside all non-[arrow](https://attacomsian.com/blog/javascript-arrow-functions) functions that represents the values of the arguments passed to that function. You can use numerical indexes to access the values of arguments from the `arguments` object. For example, the first argument can be accessed as `arguments[0]`, the second argument can be accessed as `arguments[1]`, and so on.

The `arguments` object is a lot like an [array](https://attacomsian.com/blog/javascript-arrays), but it is not a real array. Although it has the `length` property, you can not use the common array methods like `map()`, `slice()`, and `filter()` on it.

There are multiple ways to convert an `arguments` object to a true `Array` object.

## Rest Parameters

The [rest parameter](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters) syntax was introduced in ES6 to represent an unspecified number of arguments as an array. To use rest parameters, you can prefix the function's last parameter with `...` (spread operator). It will convert all remaining user-supplied arguments into a standard JavaScript array.

Since the rest parameter is a real `Array` instance, unlike the `arguments` object, you do not need to perform any conversion:

```javascript
const sort = (...numbers) => {
  return numbers.sort((a, b) => a - b)
}

sort(1, 4, 5, 2)
// [ 1, 2, 4, 5 ]
```

## `Array.from()` Method

Another way to convert the `arguments` object to an array in ES6 is by using the [`Array.from()`](https://attacomsian.com/blog/javascript-array-from) method. This method converts an array-like or iterable object into an `Array` instance:

```javascript
function sort() {
  return Array.from(arguments).sort((a, b) => a - b)
}

sort(1, 4, 5, 2)
// [ 1, 2, 4, 5 ]
```

## `Array.prototype.slice()` Method

Finally, the last method to convert an `arguments` object to an array is the `Array.prototype.slice()` method. Much like converting a [NodeList to an array](https://attacomsian.com/blog/javascript-convert-nodelist-to-array#arrayprototypeslice-method), the `Array.slice()` method takes in the `arguments` object and transforms it into an actual array:

```javascript
function sort() {
  const args = Array.prototype.slice.call(arguments)
  return args.sort((a, b) => a - b)
}

const sorted = sort(1, 4, 5, 2)

console.log(sorted)
// [ 1, 2, 4, 5 ]
```

You can also use a concise form of the `slice()` method:

```javascript
const args = [].slice.call(arguments)
```

The `Array.prototype.slice.call()` works in all modern and old browsers, including IE 6+. You should use this approach if you want to support old browsers.

To learn more about JavaScript arrays and how to store multiple pieces of information in one single variable, read [this guide](https://attacomsian.com/blog/javascript-arrays).