# Source: https://oxc.rs/docs/guide/usage/linter/rules/unicorn/no-array-reduce.md

## What it does

Disallow `Array#reduce()` and `Array#reduceRight()`.

## Why is this bad?

`Array#reduce()` and `Array#reduceRight()` usually result in [hard-to-read](https://twitter.com/jaffathecake/status/1213077702300852224) and [less performant](https://www.richsnapp.com/article/2019/06-09-reduce-spread-anti-pattern) code. In almost every case, it can be replaced by `.map`, `.filter`, or a `for-of` loop.

It's only somewhat useful in the rare case of summing up numbers, which is allowed by default.

## Examples

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

```javascript
array.reduce(reducer, initialValue);
array.reduceRight(reducer, initialValue);
```

## Configuration

This rule accepts a configuration object with the following properties:

## allowSimpleOperations

type: `boolean`

default: `true`

When set to `true`, allows simple operations (like summing numbers) in `reduce` and `reduceRight` calls.

## How to use

To **enable** this rule using the config file or in the CLI, you can use:

::: code-group

```json [Config (.oxlintrc.json)]
{
  "rules": {
    "unicorn/no-array-reduce": "error"
  }
}
```

```bash [CLI]
oxlint --deny unicorn/no-array-reduce
```

:::

## References

* Rule Source