---
url: /docs/guide/usage/linter/rules/unicorn/prefer-native-coercion-functions.md
---

### What it does

Prefers built-in functions over custom ones with the same functionality.

### Why is this bad?

If a function is equivalent to [`String`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String), [`Number`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number), [`BigInt`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt), [`Boolean`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean), or [`Symbol`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol), you should use the built-in one directly.
Wrapping the built-in in a function is moot.

### Examples

Examples of **incorrect** code for this rule:

```javascript
const foo = (v) => String(v);
foo(1);
const foo = (v) => Number(v);
array.some((v) => /* comment */ v);
```

Examples of **correct** code for this rule:

```javascript
String(1);
Number(1);
array.some(Boolean);
```

## How to use

## Version

This rule was added in v0.0.19.

## References