# eslint-plugin-unicorn [![Coverage Status](https://codecov.io/gh/sindresorhus/eslint-plugin-unicorn/branch/main/graph/badge.svg)](https://codecov.io/gh/sindresorhus/eslint-plugin-unicorn/branch/main) [![npm version](https://img.shields.io/npm/v/eslint-plugin-unicorn.svg?style=flat)](https://npmjs.com/package/eslint-plugin-unicorn) Unicorn > More than 100 powerful ESLint rules You might want to check out [XO](https://github.com/xojs/xo), which includes this plugin. [**Propose or contribute a new rule ➑**](.github/contributing.md) ## Install ```sh npm install --save-dev eslint eslint-plugin-unicorn ``` **Requires ESLint `>=9.20.0`, [flat config](https://eslint.org/docs/latest/use/configure/configuration-files), and [ESM](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c#how-can-i-make-my-typescript-project-output-esm).** ## Usage Use a [preset config](#preset-configs) or configure each rule in `eslint.config.js`. If you don't use the preset, ensure you use the same `languageOptions` config as below. ```js import eslintPluginUnicorn from 'eslint-plugin-unicorn'; import globals from 'globals'; export default [ { languageOptions: { globals: globals.builtin, }, plugins: { unicorn: eslintPluginUnicorn, }, rules: { 'unicorn/better-regex': 'error', 'unicorn/…': 'error', }, }, // … ]; ``` ## Rules πŸ’Ό [Configurations](https://github.com/sindresorhus/eslint-plugin-unicorn#recommended-config) enabled in.\ βœ… Set in the `recommended` [configuration](https://github.com/sindresorhus/eslint-plugin-unicorn#recommended-config).\ β˜‘οΈ Set in the `unopinionated` [configuration](https://github.com/sindresorhus/eslint-plugin-unicorn#recommended-config).\ πŸ”§ Automatically fixable by the [`--fix` CLI option](https://eslint.org/docs/user-guide/command-line-interface#--fix).\ πŸ’‘ Manually fixable by [editor suggestions](https://eslint.org/docs/latest/use/core-concepts#rule-suggestions). | NameΒ Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β Β  | Description | πŸ’Ό | πŸ”§ | πŸ’‘ | | :----------------------------------------------------------------------------------------------- | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :--- | :- | :- | | [better-regex](docs/rules/better-regex.md) | Improve regexes by making them shorter, consistent, and safer. | | πŸ”§ | | | [catch-error-name](docs/rules/catch-error-name.md) | Enforce a specific parameter name in catch clauses. | βœ… | πŸ”§ | | | [consistent-assert](docs/rules/consistent-assert.md) | Enforce consistent assertion style with `node:assert`. | βœ… | πŸ”§ | | | [consistent-date-clone](docs/rules/consistent-date-clone.md) | Prefer passing `Date` directly to the constructor when cloning. | βœ… β˜‘οΈ | πŸ”§ | | | [consistent-destructuring](docs/rules/consistent-destructuring.md) | Use destructured variables over properties. | | | πŸ’‘ | | [consistent-empty-array-spread](docs/rules/consistent-empty-array-spread.md) | Prefer consistent types when spreading a ternary in an array literal. | βœ… | πŸ”§ | | | [consistent-existence-index-check](docs/rules/consistent-existence-index-check.md) | Enforce consistent style for element existence checks with `indexOf()`, `lastIndexOf()`, `findIndex()`, and `findLastIndex()`. | βœ… β˜‘οΈ | πŸ”§ | | | [consistent-function-scoping](docs/rules/consistent-function-scoping.md) | Move function definitions to the highest possible scope. | βœ… | | | | [consistent-template-literal-escape](docs/rules/consistent-template-literal-escape.md) | Enforce consistent style for escaping `${` in template literals. | βœ… | πŸ”§ | | | [custom-error-definition](docs/rules/custom-error-definition.md) | Enforce correct `Error` subclassing. | | πŸ”§ | | | [empty-brace-spaces](docs/rules/empty-brace-spaces.md) | Enforce no spaces between braces. | βœ… | πŸ”§ | | | [error-message](docs/rules/error-message.md) | Enforce passing a `message` value when creating a built-in error. | βœ… β˜‘οΈ | | | | [escape-case](docs/rules/escape-case.md) | Require escape sequences to use uppercase or lowercase values. | βœ… β˜‘οΈ | πŸ”§ | | | [expiring-todo-comments](docs/rules/expiring-todo-comments.md) | Add expiration conditions to TODO comments. | βœ… β˜‘οΈ | | | | [explicit-length-check](docs/rules/explicit-length-check.md) | Enforce explicitly comparing the `length` or `size` property of a value. | βœ… | πŸ”§ | πŸ’‘ | | [filename-case](docs/rules/filename-case.md) | Enforce a case style for filenames. | βœ… | | | | [import-style](docs/rules/import-style.md) | Enforce specific import styles per module. | βœ… β˜‘οΈ | | | | [isolated-functions](docs/rules/isolated-functions.md) | Prevent usage of variables from outside the scope of isolated functions. | βœ… | | | | [new-for-builtins](docs/rules/new-for-builtins.md) | Enforce the use of `new` for all builtins, except `String`, `Number`, `Boolean`, `Symbol` and `BigInt`. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [no-abusive-eslint-disable](docs/rules/no-abusive-eslint-disable.md) | Enforce specifying rules to disable in `eslint-disable` comments. | βœ… β˜‘οΈ | | | | [no-accessor-recursion](docs/rules/no-accessor-recursion.md) | Disallow recursive access to `this` within getters and setters. | βœ… β˜‘οΈ | | | | [no-anonymous-default-export](docs/rules/no-anonymous-default-export.md) | Disallow anonymous functions and classes as the default export. | βœ… β˜‘οΈ | | πŸ’‘ | | [no-array-callback-reference](docs/rules/no-array-callback-reference.md) | Prevent passing a function reference directly to iterator methods. | βœ… | | πŸ’‘ | | [no-array-for-each](docs/rules/no-array-for-each.md) | Prefer `for…of` over the `forEach` method. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [no-array-method-this-argument](docs/rules/no-array-method-this-argument.md) | Disallow using the `this` argument in array methods. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [no-array-reduce](docs/rules/no-array-reduce.md) | Disallow `Array#reduce()` and `Array#reduceRight()`. | βœ… | | | | [no-array-reverse](docs/rules/no-array-reverse.md) | Prefer `Array#toReversed()` over `Array#reverse()`. | βœ… β˜‘οΈ | | πŸ’‘ | | [no-array-sort](docs/rules/no-array-sort.md) | Prefer `Array#toSorted()` over `Array#sort()`. | βœ… β˜‘οΈ | | πŸ’‘ | | [no-await-expression-member](docs/rules/no-await-expression-member.md) | Disallow member access from await expression. | βœ… | πŸ”§ | | | [no-await-in-promise-methods](docs/rules/no-await-in-promise-methods.md) | Disallow using `await` in `Promise` method parameters. | βœ… β˜‘οΈ | | πŸ’‘ | | [no-console-spaces](docs/rules/no-console-spaces.md) | Do not use leading/trailing space between `console.log` parameters. | βœ… β˜‘οΈ | πŸ”§ | | | [no-document-cookie](docs/rules/no-document-cookie.md) | Do not use `document.cookie` directly. | βœ… β˜‘οΈ | | | | [no-empty-file](docs/rules/no-empty-file.md) | Disallow empty files. | βœ… β˜‘οΈ | | | | [no-for-loop](docs/rules/no-for-loop.md) | Do not use a `for` loop that can be replaced with a `for-of` loop. | βœ… | πŸ”§ | πŸ’‘ | | [no-hex-escape](docs/rules/no-hex-escape.md) | Enforce the use of Unicode escapes instead of hexadecimal escapes. | βœ… β˜‘οΈ | πŸ”§ | | | [no-immediate-mutation](docs/rules/no-immediate-mutation.md) | Disallow immediate mutation after variable assignment. | βœ… | πŸ”§ | πŸ’‘ | | [no-instanceof-builtins](docs/rules/no-instanceof-builtins.md) | Disallow `instanceof` with built-in objects | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [no-invalid-fetch-options](docs/rules/no-invalid-fetch-options.md) | Disallow invalid options in `fetch()` and `new Request()`. | βœ… β˜‘οΈ | | | | [no-invalid-remove-event-listener](docs/rules/no-invalid-remove-event-listener.md) | Prevent calling `EventTarget#removeEventListener()` with the result of an expression. | βœ… β˜‘οΈ | | | | [no-keyword-prefix](docs/rules/no-keyword-prefix.md) | Disallow identifiers starting with `new` or `class`. | | | | | [no-lonely-if](docs/rules/no-lonely-if.md) | Disallow `if` statements as the only statement in `if` blocks without `else`. | βœ… β˜‘οΈ | πŸ”§ | | | [no-magic-array-flat-depth](docs/rules/no-magic-array-flat-depth.md) | Disallow a magic number as the `depth` argument in `Array#flat(…).` | βœ… β˜‘οΈ | | | | [no-named-default](docs/rules/no-named-default.md) | Disallow named usage of default import and export. | βœ… β˜‘οΈ | πŸ”§ | | | [no-negated-condition](docs/rules/no-negated-condition.md) | Disallow negated conditions. | βœ… β˜‘οΈ | πŸ”§ | | | [no-negation-in-equality-check](docs/rules/no-negation-in-equality-check.md) | Disallow negated expression in equality check. | βœ… β˜‘οΈ | | πŸ’‘ | | [no-nested-ternary](docs/rules/no-nested-ternary.md) | Disallow nested ternary expressions. | βœ… | πŸ”§ | | | [no-new-array](docs/rules/no-new-array.md) | Disallow `new Array()`. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [no-new-buffer](docs/rules/no-new-buffer.md) | Enforce the use of `Buffer.from()` and `Buffer.alloc()` instead of the deprecated `new Buffer()`. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [no-null](docs/rules/no-null.md) | Disallow the use of the `null` literal. | βœ… | πŸ”§ | πŸ’‘ | | [no-object-as-default-parameter](docs/rules/no-object-as-default-parameter.md) | Disallow the use of objects as default parameters. | βœ… β˜‘οΈ | | | | [no-process-exit](docs/rules/no-process-exit.md) | Disallow `process.exit()`. | βœ… β˜‘οΈ | | | | [no-single-promise-in-promise-methods](docs/rules/no-single-promise-in-promise-methods.md) | Disallow passing single-element arrays to `Promise` methods. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [no-static-only-class](docs/rules/no-static-only-class.md) | Disallow classes that only have static members. | βœ… β˜‘οΈ | πŸ”§ | | | [no-thenable](docs/rules/no-thenable.md) | Disallow `then` property. | βœ… β˜‘οΈ | | | | [no-this-assignment](docs/rules/no-this-assignment.md) | Disallow assigning `this` to a variable. | βœ… β˜‘οΈ | | | | [no-typeof-undefined](docs/rules/no-typeof-undefined.md) | Disallow comparing `undefined` using `typeof`. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [no-unnecessary-array-flat-depth](docs/rules/no-unnecessary-array-flat-depth.md) | Disallow using `1` as the `depth` argument of `Array#flat()`. | βœ… β˜‘οΈ | πŸ”§ | | | [no-unnecessary-array-splice-count](docs/rules/no-unnecessary-array-splice-count.md) | Disallow using `.length` or `Infinity` as the `deleteCount` or `skipCount` argument of `Array#{splice,toSpliced}()`. | βœ… β˜‘οΈ | πŸ”§ | | | [no-unnecessary-await](docs/rules/no-unnecessary-await.md) | Disallow awaiting non-promise values. | βœ… β˜‘οΈ | πŸ”§ | | | [no-unnecessary-polyfills](docs/rules/no-unnecessary-polyfills.md) | Enforce the use of built-in methods instead of unnecessary polyfills. | βœ… β˜‘οΈ | | | | [no-unnecessary-slice-end](docs/rules/no-unnecessary-slice-end.md) | Disallow using `.length` or `Infinity` as the `end` argument of `{Array,String,TypedArray}#slice()`. | βœ… β˜‘οΈ | πŸ”§ | | | [no-unreadable-array-destructuring](docs/rules/no-unreadable-array-destructuring.md) | Disallow unreadable array destructuring. | βœ… β˜‘οΈ | πŸ”§ | | | [no-unreadable-iife](docs/rules/no-unreadable-iife.md) | Disallow unreadable IIFEs. | βœ… β˜‘οΈ | | | | [no-unused-properties](docs/rules/no-unused-properties.md) | Disallow unused object properties. | | | | | [no-useless-collection-argument](docs/rules/no-useless-collection-argument.md) | Disallow useless values or fallbacks in `Set`, `Map`, `WeakSet`, or `WeakMap`. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [no-useless-error-capture-stack-trace](docs/rules/no-useless-error-capture-stack-trace.md) | Disallow unnecessary `Error.captureStackTrace(…)`. | βœ… β˜‘οΈ | πŸ”§ | | | [no-useless-fallback-in-spread](docs/rules/no-useless-fallback-in-spread.md) | Disallow useless fallback when spreading in object literals. | βœ… β˜‘οΈ | πŸ”§ | | | [no-useless-iterator-to-array](docs/rules/no-useless-iterator-to-array.md) | Disallow unnecessary `.toArray()` on iterators. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [no-useless-length-check](docs/rules/no-useless-length-check.md) | Disallow useless array length check. | βœ… β˜‘οΈ | πŸ”§ | | | [no-useless-promise-resolve-reject](docs/rules/no-useless-promise-resolve-reject.md) | Disallow returning/yielding `Promise.resolve/reject()` in async functions or promise callbacks | βœ… β˜‘οΈ | πŸ”§ | | | [no-useless-spread](docs/rules/no-useless-spread.md) | Disallow unnecessary spread. | βœ… β˜‘οΈ | πŸ”§ | | | [no-useless-switch-case](docs/rules/no-useless-switch-case.md) | Disallow useless case in switch statements. | βœ… β˜‘οΈ | | πŸ’‘ | | [no-useless-undefined](docs/rules/no-useless-undefined.md) | Disallow useless `undefined`. | βœ… β˜‘οΈ | πŸ”§ | | | [no-zero-fractions](docs/rules/no-zero-fractions.md) | Disallow number literals with zero fractions or dangling dots. | βœ… β˜‘οΈ | πŸ”§ | | | [number-literal-case](docs/rules/number-literal-case.md) | Enforce proper case for numeric literals. | βœ… β˜‘οΈ | πŸ”§ | | | [numeric-separators-style](docs/rules/numeric-separators-style.md) | Enforce the style of numeric separators by correctly grouping digits. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-add-event-listener](docs/rules/prefer-add-event-listener.md) | Prefer `.addEventListener()` and `.removeEventListener()` over `on`-functions. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-array-find](docs/rules/prefer-array-find.md) | Prefer `.find(…)` and `.findLast(…)` over the first or last element from `.filter(…)`. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-array-flat](docs/rules/prefer-array-flat.md) | Prefer `Array#flat()` over legacy techniques to flatten arrays. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-array-flat-map](docs/rules/prefer-array-flat-map.md) | Prefer `.flatMap(…)` over `.map(…).flat()`. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-array-index-of](docs/rules/prefer-array-index-of.md) | Prefer `Array#{indexOf,lastIndexOf}()` over `Array#{findIndex,findLastIndex}()` when looking for the index of an item. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-array-some](docs/rules/prefer-array-some.md) | Prefer `.some(…)` over `.filter(…).length` check and `.{find,findLast,findIndex,findLastIndex}(…)`. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-at](docs/rules/prefer-at.md) | Prefer `.at()` method for index access and `String#charAt()`. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-bigint-literals](docs/rules/prefer-bigint-literals.md) | Prefer `BigInt` literals over the constructor. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-blob-reading-methods](docs/rules/prefer-blob-reading-methods.md) | Prefer `Blob#arrayBuffer()` over `FileReader#readAsArrayBuffer(…)` and `Blob#text()` over `FileReader#readAsText(…)`. | βœ… β˜‘οΈ | | | | [prefer-class-fields](docs/rules/prefer-class-fields.md) | Prefer class field declarations over `this` assignments in constructors. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-classlist-toggle](docs/rules/prefer-classlist-toggle.md) | Prefer using `Element#classList.toggle()` to toggle class names. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-code-point](docs/rules/prefer-code-point.md) | Prefer `String#codePointAt(…)` over `String#charCodeAt(…)` and `String.fromCodePoint(…)` over `String.fromCharCode(…)`. | βœ… β˜‘οΈ | | πŸ’‘ | | [prefer-date-now](docs/rules/prefer-date-now.md) | Prefer `Date.now()` to get the number of milliseconds since the Unix Epoch. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-default-parameters](docs/rules/prefer-default-parameters.md) | Prefer default parameters over reassignment. | βœ… β˜‘οΈ | | πŸ’‘ | | [prefer-dom-node-append](docs/rules/prefer-dom-node-append.md) | Prefer `Node#append()` over `Node#appendChild()`. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-dom-node-dataset](docs/rules/prefer-dom-node-dataset.md) | Prefer using `.dataset` on DOM elements over calling attribute methods. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-dom-node-remove](docs/rules/prefer-dom-node-remove.md) | Prefer `childNode.remove()` over `parentNode.removeChild(childNode)`. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-dom-node-text-content](docs/rules/prefer-dom-node-text-content.md) | Prefer `.textContent` over `.innerText`. | βœ… β˜‘οΈ | | πŸ’‘ | | [prefer-event-target](docs/rules/prefer-event-target.md) | Prefer `EventTarget` over `EventEmitter`. | βœ… β˜‘οΈ | | | | [prefer-export-from](docs/rules/prefer-export-from.md) | Prefer `export…from` when re-exporting. | βœ… | πŸ”§ | πŸ’‘ | | [prefer-global-this](docs/rules/prefer-global-this.md) | Prefer `globalThis` over `window`, `self`, and `global`. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-import-meta-properties](docs/rules/prefer-import-meta-properties.md) | Prefer `import.meta.{dirname,filename}` over legacy techniques for getting file paths. | | πŸ”§ | | | [prefer-includes](docs/rules/prefer-includes.md) | Prefer `.includes()` over `.indexOf()`, `.lastIndexOf()`, and `Array#some()` when checking for existence or non-existence. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-json-parse-buffer](docs/rules/prefer-json-parse-buffer.md) | Prefer reading a JSON file as a buffer. | | πŸ”§ | | | [prefer-keyboard-event-key](docs/rules/prefer-keyboard-event-key.md) | Prefer `KeyboardEvent#key` over `KeyboardEvent#keyCode`. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-logical-operator-over-ternary](docs/rules/prefer-logical-operator-over-ternary.md) | Prefer using a logical operator over a ternary. | βœ… β˜‘οΈ | | πŸ’‘ | | [prefer-math-min-max](docs/rules/prefer-math-min-max.md) | Prefer `Math.min()` and `Math.max()` over ternaries for simple comparisons. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-math-trunc](docs/rules/prefer-math-trunc.md) | Enforce the use of `Math.trunc` instead of bitwise operators. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-modern-dom-apis](docs/rules/prefer-modern-dom-apis.md) | Prefer `.before()` over `.insertBefore()`, `.replaceWith()` over `.replaceChild()`, prefer one of `.before()`, `.after()`, `.append()` or `.prepend()` over `insertAdjacentText()` and `insertAdjacentElement()`. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-modern-math-apis](docs/rules/prefer-modern-math-apis.md) | Prefer modern `Math` APIs over legacy patterns. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-module](docs/rules/prefer-module.md) | Prefer JavaScript modules (ESM) over CommonJS. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-native-coercion-functions](docs/rules/prefer-native-coercion-functions.md) | Prefer using `String`, `Number`, `BigInt`, `Boolean`, and `Symbol` directly. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-negative-index](docs/rules/prefer-negative-index.md) | Prefer negative index over `.length - index` when possible. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-node-protocol](docs/rules/prefer-node-protocol.md) | Prefer using the `node:` protocol when importing Node.js builtin modules. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-number-properties](docs/rules/prefer-number-properties.md) | Prefer `Number` static properties over global ones. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-object-from-entries](docs/rules/prefer-object-from-entries.md) | Prefer using `Object.fromEntries(…)` to transform a list of key-value pairs into an object. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-optional-catch-binding](docs/rules/prefer-optional-catch-binding.md) | Prefer omitting the `catch` binding parameter. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-prototype-methods](docs/rules/prefer-prototype-methods.md) | Prefer borrowing methods from the prototype instead of the instance. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-query-selector](docs/rules/prefer-query-selector.md) | Prefer `.querySelector()` over `.getElementById()`, `.querySelectorAll()` over `.getElementsByClassName()` and `.getElementsByTagName()` and `.getElementsByName()`. | βœ… | πŸ”§ | | | [prefer-reflect-apply](docs/rules/prefer-reflect-apply.md) | Prefer `Reflect.apply()` over `Function#apply()`. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-regexp-test](docs/rules/prefer-regexp-test.md) | Prefer `RegExp#test()` over `String#match()` and `RegExp#exec()`. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-response-static-json](docs/rules/prefer-response-static-json.md) | Prefer `Response.json()` over `new Response(JSON.stringify())`. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-set-has](docs/rules/prefer-set-has.md) | Prefer `Set#has()` over `Array#includes()` when checking for existence or non-existence. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-set-size](docs/rules/prefer-set-size.md) | Prefer using `Set#size` instead of `Array#length`. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-simple-condition-first](docs/rules/prefer-simple-condition-first.md) | Prefer simple conditions first in logical expressions. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-single-call](docs/rules/prefer-single-call.md) | Enforce combining multiple `Array#push()`, `Element#classList.{add,remove}()`, and `importScripts()` into one call. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-spread](docs/rules/prefer-spread.md) | Prefer the spread operator over `Array.from(…)`, `Array#concat(…)`, `Array#{slice,toSpliced}()` and `String#split('')`. | βœ… | πŸ”§ | πŸ’‘ | | [prefer-string-raw](docs/rules/prefer-string-raw.md) | Prefer using the `String.raw` tag to avoid escaping `\`. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-string-replace-all](docs/rules/prefer-string-replace-all.md) | Prefer `String#replaceAll()` over regex searches with the global flag. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-string-slice](docs/rules/prefer-string-slice.md) | Prefer `String#slice()` over `String#substr()` and `String#substring()`. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-string-starts-ends-with](docs/rules/prefer-string-starts-ends-with.md) | Prefer `String#startsWith()` & `String#endsWith()` over `RegExp#test()`. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [prefer-string-trim-start-end](docs/rules/prefer-string-trim-start-end.md) | Prefer `String#trimStart()` / `String#trimEnd()` over `String#trimLeft()` / `String#trimRight()`. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-structured-clone](docs/rules/prefer-structured-clone.md) | Prefer using `structuredClone` to create a deep clone. | βœ… β˜‘οΈ | | πŸ’‘ | | [prefer-switch](docs/rules/prefer-switch.md) | Prefer `switch` over multiple `else-if`. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-ternary](docs/rules/prefer-ternary.md) | Prefer ternary expressions over simple `if-else` statements. | βœ… β˜‘οΈ | πŸ”§ | | | [prefer-top-level-await](docs/rules/prefer-top-level-await.md) | Prefer top-level await over top-level promises and async function calls. | βœ… β˜‘οΈ | | πŸ’‘ | | [prefer-type-error](docs/rules/prefer-type-error.md) | Enforce throwing `TypeError` in type checking conditions. | βœ… β˜‘οΈ | πŸ”§ | | | [prevent-abbreviations](docs/rules/prevent-abbreviations.md) | Prevent abbreviations. | βœ… | πŸ”§ | | | [relative-url-style](docs/rules/relative-url-style.md) | Enforce consistent relative URL style. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [require-array-join-separator](docs/rules/require-array-join-separator.md) | Enforce using the separator argument with `Array#join()`. | βœ… β˜‘οΈ | πŸ”§ | | | [require-module-attributes](docs/rules/require-module-attributes.md) | Require non-empty module attributes for imports and exports | βœ… β˜‘οΈ | πŸ”§ | | | [require-module-specifiers](docs/rules/require-module-specifiers.md) | Require non-empty specifier list in import and export statements. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [require-number-to-fixed-digits-argument](docs/rules/require-number-to-fixed-digits-argument.md) | Enforce using the digits argument with `Number#toFixed()`. | βœ… β˜‘οΈ | πŸ”§ | | | [require-post-message-target-origin](docs/rules/require-post-message-target-origin.md) | Enforce using the `targetOrigin` argument with `window.postMessage()`. | | | πŸ’‘ | | [string-content](docs/rules/string-content.md) | Enforce better string content. | | πŸ”§ | πŸ’‘ | | [switch-case-braces](docs/rules/switch-case-braces.md) | Enforce consistent brace style for `case` clauses. | βœ… | πŸ”§ | | | [switch-case-break-position](docs/rules/switch-case-break-position.md) | Enforce consistent `break`/`return`/`continue`/`throw` position in `case` clauses. | βœ… | πŸ”§ | | | [template-indent](docs/rules/template-indent.md) | Fix whitespace-insensitive template indentation. | βœ… | πŸ”§ | | | [text-encoding-identifier-case](docs/rules/text-encoding-identifier-case.md) | Enforce consistent case for text encoding identifiers. | βœ… β˜‘οΈ | πŸ”§ | πŸ’‘ | | [throw-new-error](docs/rules/throw-new-error.md) | Require `new` when creating an error. | βœ… β˜‘οΈ | πŸ”§ | | ### Deleted and deprecated rules See [the list](docs/deleted-and-deprecated-rules.md). ## Preset configs See the [ESLint docs](https://eslint.org/docs/latest/use/configure/configuration-files) for more information about extending config files. **Note**: Preset configs will also enable the correct [language options](https://eslint.org/docs/latest/use/configure/language-options). ### Recommended config This plugin exports a `recommended` config that enforces good practices. ```js import eslintPluginUnicorn from 'eslint-plugin-unicorn'; export default [ // … eslintPluginUnicorn.configs.recommended, { rules: { 'unicorn/better-regex': 'warn', }, }, ]; ``` ### All config This plugin exports an `all` that makes use of all rules (except for deprecated ones). ```js import eslintPluginUnicorn from 'eslint-plugin-unicorn'; export default [ // … eslintPluginUnicorn.configs.all, { rules: { 'unicorn/better-regex': 'warn', }, }, ]; ``` ## Maintainers - [Sindre Sorhus](https://github.com/sindresorhus) - [Fisker Cheung](https://github.com/fisker) - [Bryan Mishkin](https://github.com/bmish) - [futpib](https://github.com/futpib) ### Former - [Jeroen Engels](https://github.com/jfmengels) - [Sam Verschueren](https://github.com/SamVerschueren) - [Adam Babcock](https://github.com/MrHen)