![\"ESLint](\"https://i.imgur.com/De2l7rX.png\")
📦 Zero-config ESLint + Prettier setup for JS/React/Node projects with deterministic installs and modern flat config.
\n\n# Welcome to ESLint config Cecilia\n\n[](https://badge.fury.io/js/eslint-config-cecilia)\n\n[](LICENSE)\n[](https://github.com/SandroMiguel)\n\n**ESLint configuration for my projects.**\n\nESLint config Cecilia is an opinionated\n[shareable ESLint config](http://eslint.org/docs/developer-guide/shareable-configs.html)\nused in my JavaScript projects ([Vanilla.js](http://vanilla-js.com/),\n[React.js](https://reactjs.org/) or [Node.js](https://nodejs.org/)).\n\n## Table of Contents\n\n1. [Goals](#goals)\n1. [Installation](#installation)\n1. [Stability](#stability)\n1. [Debugging](#debugging)\n1. [Credits](#credits)\n1. [Contributing](#contributing)\n1. [Questions](#questions)\n1. [License](#license)\n\n## Goals\n\n- I want to use [ESLint](https://eslint.org/) to lint my files using the modern flat config\n- I want to use [Prettier](https://www.npmjs.com/package/prettier) as a standalone formatter (not inside ESLint)\n- I want a fast and predictable linting experience (no heavy or legacy configs)\n- I want to keep the code clean and consistent across several projects\n- I want to avoid maintaining complex ESLint setups across projects\n- I want consistent and deterministic linting behavior across all environments\n- I want built-in support for code quality, documentation (JSDoc), and modern best practices\n- I want ESLint core recommended rules enabled by default for baseline security and code quality\n\n## Installation\n\n### Set up the config automatically (recommended)\n\n#### With npm\n\n```sh\nnpm i -D eslint-config-cecilia\nnpx cecilia\n```\n\n#### Or with Yarn\n\n```sh\nyarn add --dev eslint-config-cecilia\nyarn cecilia\n```\n\n1. Select \"1\" or \"2\" to install the necessary dependencies with npm/Yarn\n1. Select the type of project: React (1) Node (2) Both (3) None (4)\n1. Select \"y\" to create the `eslint.config.mjs` file\n1. Select \"y\" to create the `.prettierrc.js` file\n1. Select \"y\" to add the `lint` script commands in your `package.json`\n\n#### Optional - Override Rules or Ignore Patterns\n\nUse the `eslint.config.mjs` if you want to override, extend or add ignore patterns to the config:\n\n```\n// eslint.config.mjs\nimport cecilia from 'eslint-config-cecilia'\n\nexport default [\n // First block for ignores (optional, to add more ignores)\n {\n ignores: [\n '**/custom-ignored-folder/**',\n ],\n },\n\n // Default cecilia config\n ...cecilia,\n\n // Block for custom rules\n {\n rules: {\n 'no-console': 'off',\n // your custom rules here\n },\n },\n]\n```\n\nFor more information, see \"[ESLint Config Files](https://eslint.org/docs/latest/use/configure/configuration-files#using-eslintconfigjs)\".\n\n**Pro tip**\n\nCheck the [list of available rules](https://eslint.org/docs/rules/).\n\n**Optional - Specifying Environments**\n\nTo specify environments, add a block with `env`:\n\n```\n// eslint.config.mjs\nimport cecilia from 'eslint-config-cecilia'\n\nexport default [\n ...cecilia,\n {\n env: {\n browser: true,\n node: true,\n es2023: true,\n },\n },\n]\n```\n\n**Optional - Use `.prettierrc.js` file to change some rules**\n\nExample:\n\n```\nmodule.exports = {\n semi: false,\n singleQuote: true,\n trailingComma: 'all',\n}\n```\n\n**Optional - Add scripts to the `package.json` file**\n\nOpen the `package.json` file and add the following scripts entries:\n\n```\n ...\n\n \"scripts\": {\n \"lint\": \"eslint \\\"src/**/*.{js,jsx}\\\" --cache\",\n \"lint:fix\": \"eslint \\\"src/**/*.{js,jsx}\\\" --fix --cache\",\n \"format\": \"prettier --write .\"\n }\n\n ...\n```\n\n### Usage\n\n#### Run the script\n\n`yarn lint` or `npm run lint` to lint your code (fast with cache).\n\n`yarn lint:fix` or `npm run lint:fix` to lint and fix your code.\n\n`yarn format` or `npm run format` to format your code using Prettier.\n\n**Pro tip**\n\nInstall\n[ESLint](https://marketplace.visualstudio.com/items?itemName=dbaeumer.vscode-eslint)\nand\n[Prettier](https://marketplace.visualstudio.com/items?itemName=esbenp.prettier-vscode)\nextensions for Visual Studio Code.\n\n## Stability\n\nCecilia installs all dependencies using fixed versions to ensure deterministic behavior.\n\nThis means:\n\n- The linting results are consistent across machines and environments\n- No unexpected rule changes after reinstalling dependencies\n- Updates only happen when you explicitly upgrade Cecilia\n- No hidden performance regressions caused by third-party configs\n\nThis avoids common issues caused by version ranges (e.g. `^`) where plugin updates can silently change linting behavior.\n\n## Debugging\n\nIt will print the resolved config, including all rules and plugins used internally.\n\n```sh\nnpx cecilia-debug\n```\n\nIt will print the resolved config, including all extended rules and environments, like this:\n\n```json\n{\n \"extends\": [\n \"@eslint/js (recommended)\",\n \"./rules/unicorn.js\",\n \"./rules/jsdoc.js\",\n \"./rules/react-hooks.js\",\n \"./rules/react.js\",\n \"./rules/cecilia.js\"\n ],\n \"env\": {\n \"browser\": true,\n \"jest\": true,\n \"node\": true\n },\n \"parserOptions\": {\n \"ecmaVersion\": \"latest\",\n \"sourceType\": \"module\",\n \"ecmaFeatures\": { \"jsx\": true }\n }\n}\n```\n\n## Credits\n\n- Linting - [ESLint](https://eslint.org/)\n- Code formatter - [Prettier](https://www.npmjs.com/package/prettier)\n\n### Core Rules\n\n- [@eslint/js](https://www.npmjs.com/package/@eslint/js) recommended rules\n - Includes essential rules like `no-undef`, `no-unused-vars`, `no-debugger`, `no-cond-assign`, etc.\n\n### Plugins\n\n- [eslint-plugin-react](https://www.npmjs.com/package/eslint-plugin-react)\n- [eslint-plugin-react-hooks](https://www.npmjs.com/package/eslint-plugin-react-hooks)\n- [eslint-plugin-jsx-a11y](https://www.npmjs.com/package/eslint-plugin-jsx-a11y)\n- [eslint-plugin-jsdoc](https://www.npmjs.com/package/eslint-plugin-jsdoc)\n- [eslint-plugin-unicorn](https://www.npmjs.com/package/eslint-plugin-unicorn)\n\n## Contributing\n\nWant to contribute? All contributions are welcome. Read the\n[contributing guide](CONTRIBUTING.md).\n\n## Questions\n\nIf you have questions tweet me at [@sandro_m_m](https://twitter.com/sandro_m_m)\nor [open an issue](../../issues/new).\n\n## License\n\nThis project is licensed under the MIT License - see the [LICENSE](LICENSE) file\nfor details\n\n## ~ sharing is caring ~\n\nThis project helped you? Please consider giving this repository a star :star:.\n","readmeFilename":"README.md"}