https://github.com/mkosir/eslint-plugin-no-array-reduce

🚫 ESLint rule to disallow Array.reduce() method
https://github.com/mkosir/eslint-plugin-no-array-reduce

eslint eslint-plugin eslint-rules javascript reduce typescript

Last synced: about 2 months ago
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🚫 ESLint rule to disallow Array.reduce() method

• Host: GitHub
• URL: https://github.com/mkosir/eslint-plugin-no-array-reduce
• Owner: mkosir
• License: mit
• Created: 2021-07-26T07:31:35.000Z (over 3 years ago)
• Default Branch: main
• Last Pushed: 2022-07-15T21:20:19.000Z (over 2 years ago)
• Last Synced: 2024-12-09T01:31:50.956Z (about 2 months ago)
• Topics: eslint, eslint-plugin, eslint-rules, javascript, reduce, typescript
• Language: TypeScript
• Homepage:
• Size: 2.71 MB
• Stars: 11
• Watchers: 3
• Forks: 2
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# eslint-plugin-no-array-reduce

[![npm version][npm-badge]][npm-url]

[![npm downloads][downloads-badge]][npm-url]

[![CI][build-badge]][build-url]

[![semantic-release][semantic-badge]][semantic-url]

[![prettier][prettier-badge]][prettier-url]

[![TypeScript][typescript-badge]][typescript-url]

_ESLint rule to disallow `Array.reduce()` method._

Method `reduce()` in most cases can be written as `map()`, `filter()` etc. which benefits in code readability and makes it easier to maintain for future developers.

Subjectively there are still cases where you might want to use `reduce()` with `eslint-disable`.  

There are many debates related to it:

- [Jake Archibald](https://twitter.com/jaffathecake/status/1213077702300852224)

- [Is reduce() bad](https://dev.to/jasterix/is-reduce-bad-2hhd)

- [Write more readable JavaScript](https://betterprogramming.pub/think-again-before-you-use-array-reduce-28f785b5aea9)

[![](misc/code.png)](https://twitter.com/jaffathecake/status/1213084977065279489)

## Install

```bash

npm install --save-dev eslint-plugin-no-array-reduce

```

Then extend eslint config:

```js

{

  "extends": [

    // ...

    "plugin:no-array-reduce/recommended"

  ]

}

```

## Fail

```js

const products = [

  { name: 'milk', type: 'dairy' },

  { name: 'cheese', type: 'dairy' },

  { name: 'beef', type: 'meat' },

  { name: 'chicken', type: 'meat' },

];

// Add price to each product

const productsWithPrices = products.reduce((acc, product) => acc.concat({ ...product, price: 2.7 }), []);

// Filter dairy products

const dairies = products.reduce((acc, product) => (product.type === 'dairy' ? acc.concat(product) : acc), []);

// Group products by type

const productsByType = products.reduce(

  (acc, product) => ({

    ...acc,

    [product.type]: [...(acc[product.type] || []), product],

  }),

  [],

);

```

## Pass

```js

// Add price to each product

const productsWithPrices = products.map((product) => ({ ...product, price: 2.7 }));

// Filter dairy products

const dairies = products.filter((product) => product.type === 'dairy');

// Group products by type (ECMA stage 3 - https://github.com/tc39/proposal-array-grouping)

const productsByType = products.group((product) => product.type);

```

[CodeSandbox](https://codesandbox.io/s/eslint-plugin-no-array-reduce-4cyc1i?file=/index.js)

## Contributing

All contributions are welcome!

[npm-url]: https://www.npmjs.com/package/eslint-plugin-no-array-reduce

[npm-badge]: https://img.shields.io/npm/v/eslint-plugin-no-array-reduce.svg

[downloads-badge]: https://img.shields.io/npm/dm/eslint-plugin-no-array-reduce.svg?color=blue

[build-badge]: https://github.com/mkosir/eslint-plugin-no-array-reduce/actions/workflows/main.yml/badge.svg

[build-url]: https://github.com/mkosir/eslint-plugin-no-array-reduce/actions/workflows/main.yml

[semantic-badge]: https://img.shields.io/badge/%20%20%F0%9F%93%A6%F0%9F%9A%80-semantic--release-e10079.svg

[semantic-url]: https://github.com/semantic-release/semantic-release

[prettier-badge]: https://img.shields.io/badge/code_style-prettier-ff69b4.svg

[prettier-url]: https://github.com/prettier/prettier

[typescript-badge]: https://badges.frapsoft.com/typescript/code/typescript.svg?v=101

[typescript-url]: https://github.com/microsoft/TypeScript