eslint-plugin-unicorn

More than 200 powerful ESLint rules

You might want to check out XO, which includes this plugin.

Most rules target JavaScript and TypeScript, but some also lint CSS, HTML, JSON, and Markdown when used with the matching ESLint language plugin.

Propose or contribute a new rule ➡

Install

npm install --save-dev eslint eslint-plugin-unicorn

Requires ESLint >=10.4, flat config, and ESM.

Usage

Use a preset config or configure each rule in eslint.config.js.

If you don't use a preset, set the same languageOptions as shown below.

import eslintPluginUnicorn from 'eslint-plugin-unicorn';
import globals from 'globals';

export default [
	{
		languageOptions: {
			globals: globals.builtin,
		},
		plugins: {
			unicorn: eslintPluginUnicorn,
		},
		rules: {
			'unicorn/prefer-module': 'error',
			'unicorn/…': 'error',
		},
	},
	// …
];

Rules

💼 Configurations enabled in.
✅ Set in the recommended configuration.
☑️ Set in the unopinionated configuration.
🔧 Automatically fixable by the --fix CLI option.
💡 Manually fixable by editor suggestions.

Name	Description	💼	🔧	💡
better-dom-traversing	Prefer better DOM traversal APIs.	✅ ☑️		💡
catch-error-name	Enforce a specific parameter name in catch clauses.	✅	🔧
class-reference-in-static-methods	Enforce consistent class references in static methods.	✅		💡
comment-content	Enforce better comment content.	✅	🔧
consistent-assert	Enforce consistent assertion style with `node:assert`.	✅	🔧
consistent-class-member-order	Enforce consistent class member order.	✅		💡
consistent-compound-words	Enforce consistent spelling of compound words in identifiers.	✅ ☑️		💡
consistent-date-clone	Prefer passing `Date` directly to the constructor when cloning.	✅ ☑️	🔧
consistent-destructuring	Use destructured variables over properties.			💡
consistent-empty-array-spread	Prefer consistent types when spreading a ternary in an array literal.	✅	🔧
consistent-existence-index-check	Enforce consistent style for element existence checks with `indexOf()`, `lastIndexOf()`, `findIndex()`, and `findLastIndex()`.	✅ ☑️	🔧
consistent-export-decorator-position	Enforce consistent decorator position on exported classes.	✅ ☑️	🔧
consistent-function-scoping	Move function definitions to the highest possible scope.	✅
consistent-function-style	Enforce function syntax by role.			💡
consistent-json-file-read	Enforce consistent JSON file reads before `JSON.parse()`.	✅	🔧
consistent-optional-chaining	Enforce consistent optional chaining for same-base member access.	✅ ☑️		💡
consistent-template-literal-escape	Enforce consistent style for escaping `${` in template literals.	✅	🔧
custom-error-definition	Enforce correct `Error` subclassing.		🔧
dom-node-dataset	Enforce consistent style for DOM element dataset access.	✅ ☑️	🔧
empty-brace-spaces	Enforce no spaces between braces.	✅	🔧
error-message	Enforce passing a `message` value when creating a built-in error.	✅ ☑️
escape-case	Require escape sequences to use uppercase or lowercase values.	✅ ☑️	🔧
expiring-todo-comments	Add expiration conditions to TODO comments.	✅ ☑️
explicit-length-check	Enforce explicitly comparing the `length` or `size` property of a value.	✅	🔧	💡
explicit-timer-delay	Enforce or disallow explicit `delay` argument for `setTimeout()` and `setInterval()`.	✅ ☑️	🔧
filename-case	Enforce a case style for filenames and directory names.	✅
id-match	Require identifiers to match a specified regular expression.
import-style	Enforce specific import styles per module.	✅ ☑️
isolated-functions	Prevent usage of variables from outside the scope of isolated functions.	✅
max-nested-calls	Limit the depth of nested calls.	✅
new-for-builtins	Enforce the use of `new` for all builtins, except `String`, `Number`, `Boolean`, `Symbol` and `BigInt`.	✅ ☑️	🔧	💡
no-abusive-eslint-disable	Enforce specifying rules to disable in `eslint-disable` comments.	✅ ☑️
no-accessor-recursion	Disallow recursive access to `this` within getters and setters.	✅ ☑️
no-anonymous-default-export	Disallow anonymous functions and classes as the default export.	✅ ☑️		💡
no-array-callback-reference	Prevent passing a function reference directly to iterator methods.	✅		💡
no-array-fill-with-reference-type	Disallow using reference values as `Array#fill()` values.	✅ ☑️
no-array-from-fill	Disallow `.fill()` after `Array.from({length: …})`.	✅ ☑️
no-array-method-this-argument	Disallow using the `this` argument in array methods.	✅ ☑️	🔧	💡
no-array-reduce	Disallow `Array#reduce()` and `Array#reduceRight()`.	✅	🔧
no-array-reverse	Prefer `Array#toReversed()` over `Array#reverse()`.	✅ ☑️		💡
no-array-sort	Prefer `Array#toSorted()` over `Array#sort()`.	✅ ☑️		💡
no-asterisk-prefix-in-documentation-comments	Disallow asterisk prefixes in documentation comments.		🔧
no-await-expression-member	Disallow member access from await expression.	✅	🔧
no-await-in-promise-methods	Disallow using `await` in `Promise` method parameters.	✅ ☑️		💡
no-blob-to-file	Disallow unnecessary `Blob` to `File` conversion.	✅ ☑️		💡
no-break-in-nested-loop	Disallow `break` and `continue` in nested loops and switches inside loops.	✅
no-canvas-to-image	Prefer drawing canvases directly instead of converting them to images.	✅ ☑️
no-computed-property-existence-check	Disallow dynamic object property existence checks.	✅		💡
no-confusing-array-splice	Disallow confusing uses of `Array#{splice,toSpliced}()`.	✅		💡
no-confusing-array-with	Disallow confusing uses of `Array#with()`.	✅
no-console-spaces	Do not use leading/trailing space between `console.log` parameters.	✅ ☑️	🔧
no-declarations-before-early-exit	Disallow declarations before conditional early exits when they are only used after the exit.	✅ ☑️	🔧
no-document-cookie	Do not use `document.cookie` directly.	✅ ☑️
no-duplicate-loops	Disallow `.map()` and `.filter()` in `for…of` and `for await…of` loop headers.	✅
no-duplicate-set-values	Disallow duplicate values in `Set` constructor array literals.	✅
no-empty-file	Disallow empty files.	✅ ☑️
no-error-property-assignment	Disallow assigning to built-in error properties.	✅ ☑️
no-exports-in-scripts	Disallow exports in scripts.	✅ ☑️
no-for-each	Prefer `for…of` over the `forEach` method.	✅ ☑️	🔧	💡
no-for-loop	Do not use a `for` loop that can be replaced with a `for-of` loop.	✅	🔧
no-global-object-property-assignment	Disallow assigning properties on the global object.	✅ ☑️
no-immediate-mutation	Disallow immediate mutation after variable assignment.	✅	🔧	💡
no-incorrect-query-selector	Disallow incorrect `querySelector()` and `querySelectorAll()` usage.	✅	🔧
no-incorrect-template-string-interpolation	Disallow incorrect template literal interpolation syntax.	✅ ☑️		💡
no-instanceof-builtins	Disallow `instanceof` with built-in objects	✅ ☑️	🔧	💡
no-invalid-argument-count	Disallow calling functions with an invalid number of arguments.	✅ ☑️
no-invalid-fetch-options	Disallow invalid options in `fetch()` and `new Request()`.	✅ ☑️
no-invalid-file-input-accept	Disallow invalid `accept` values on file inputs.		🔧
no-invalid-remove-event-listener	Prevent calling `EventTarget#removeEventListener()` with the result of an expression.	✅ ☑️
no-keyword-prefix	Disallow identifiers starting with `new` or `class`.
no-late-current-target-access	Disallow accessing `event.currentTarget` after the synchronous event dispatch has finished.	✅
no-lonely-if	Disallow `if` statements as the only statement in `if` blocks without `else`.	✅ ☑️	🔧
no-magic-array-flat-depth	Disallow a magic number as the `depth` argument in `Array#flat(…).`	✅ ☑️
no-manually-wrapped-comments	Disallow manually wrapped comments.		🔧
no-mismatched-map-key	Disallow checking a Map key before accessing a different key.	✅
no-named-default	Disallow named usage of default import and export.	✅ ☑️	🔧
no-negated-array-predicate	Disallow negated array predicate calls.	✅ ☑️	🔧
no-negated-comparison	Disallow negated comparisons.	✅ ☑️	🔧	💡
no-negated-condition	Disallow negated conditions.	✅ ☑️	🔧
no-negation-in-equality-check	Disallow negated expression in equality check.	✅ ☑️		💡
no-nested-ternary	Disallow nested ternary expressions.	✅	🔧
no-new-array	Disallow `new Array()`.	✅ ☑️	🔧	💡
no-new-buffer	Enforce the use of `Buffer.from()` and `Buffer.alloc()` instead of the deprecated `new Buffer()`.	✅ ☑️	🔧	💡
no-null	Disallow the use of the `null` literal.	✅	🔧	💡
no-object-as-default-parameter	Disallow the use of objects as default parameters.	✅ ☑️
no-object-methods-with-collections	Disallow `Object` methods with `Map` or `Set`.	✅		💡
no-optional-chaining-on-undeclared-variable	Disallow optional chaining on undeclared variables.	✅
no-process-exit	Disallow `process.exit()`.	✅ ☑️
no-redundant-comparison	Disallow comparisons made redundant by an equality check in the same logical AND.	✅ ☑️	🔧	💡
no-return-array-push	Disallow returning the result of `Array#push()` with arguments.	✅		💡
no-single-promise-in-promise-methods	Disallow passing single-element arrays to `Promise` methods.	✅ ☑️	🔧	💡
no-static-only-class	Disallow classes that only have static members.	✅ ☑️	🔧
no-subtraction-comparison	Prefer comparing values directly over subtracting and comparing to `0`.	✅ ☑️	🔧	💡
no-thenable	Disallow `then` property.	✅ ☑️
no-this-assignment	Disallow assigning `this` to a variable.	✅ ☑️
no-this-outside-of-class	Disallow `this` outside of classes.	✅
no-top-level-side-effects	Disallow top-level side effects in exported modules.	✅ ☑️
no-typeof-undefined	Disallow comparing `undefined` using `typeof`.	✅ ☑️	🔧	💡
no-undeclared-class-members	Require class members to be declared.	✅		💡
no-unnecessary-array-flat-depth	Disallow using `1` as the `depth` argument of `Array#flat()`.	✅ ☑️	🔧
no-unnecessary-array-splice-count	Disallow using `.length` or `Infinity` as the `deleteCount` or `skipCount` argument of `Array#{splice,toSpliced}()`.	✅ ☑️	🔧
no-unnecessary-await	Disallow awaiting non-promise values.	✅ ☑️	🔧
no-unnecessary-global-this	Disallow unnecessary `globalThis` references.	✅ ☑️	🔧
no-unnecessary-nested-ternary	Disallow unnecessary nested ternary expressions.	✅ ☑️	🔧
no-unnecessary-polyfills	Enforce the use of built-in methods instead of unnecessary polyfills.	✅ ☑️
no-unnecessary-slice-end	Disallow using `.length` or `Infinity` as the `end` argument of `{Array,String,TypedArray}#slice()`.	✅ ☑️	🔧
no-unnecessary-splice	Disallow `Array#splice()` when simpler alternatives exist.	✅	🔧
no-unreadable-array-destructuring	Disallow unreadable array destructuring.	✅ ☑️	🔧
no-unreadable-iife	Disallow unreadable IIFEs.	✅ ☑️		💡
no-unreadable-new-expression	Disallow unreadable `new` expressions.	✅
no-unreadable-object-destructuring	Disallow unreadable object destructuring.	✅ ☑️
no-unsafe-buffer-conversion	Prevent unsafe use of ArrayBuffer view `.buffer`.	✅ ☑️		💡
no-unsafe-dom-html	Disallow unsafe DOM HTML APIs.
no-unsafe-property-key	Disallow unsafe values as property keys.	✅
no-unsafe-string-replacement	Disallow non-literal replacement values in `String#replace()` and `String#replaceAll()`.	✅
no-unused-array-method-return	Disallow ignoring the return value of selected array methods.	✅ ☑️
no-unused-properties	Disallow unused object properties.
no-useless-boolean-cast	Disallow unnecessary `Boolean()` casts in array predicate callbacks.	✅ ☑️	🔧
no-useless-collection-argument	Disallow useless values or fallbacks in `Set`, `Map`, `WeakSet`, or `WeakMap`.	✅ ☑️	🔧	💡
no-useless-concat	Disallow useless concatenation of literals.	✅ ☑️	🔧
no-useless-else	Disallow `else` after a statement that exits.	✅	🔧
no-useless-error-capture-stack-trace	Disallow unnecessary `Error.captureStackTrace(…)`.	✅ ☑️	🔧
no-useless-fallback-in-spread	Disallow useless fallback when spreading in object literals.	✅ ☑️	🔧
no-useless-iterator-to-array	Disallow unnecessary `.toArray()` on iterators.	✅ ☑️	🔧	💡
no-useless-length-check	Disallow useless array length check.	✅ ☑️	🔧
no-useless-promise-resolve-reject	Disallow returning/yielding `Promise.resolve/reject()` in async functions or promise callbacks	✅ ☑️	🔧
no-useless-recursion	Disallow simple recursive function calls that can be replaced with a loop.	✅
no-useless-spread	Disallow unnecessary spread.	✅ ☑️	🔧	💡
no-useless-switch-case	Disallow useless case in switch statements.	✅ ☑️		💡
no-useless-template-literals	Disallow useless template literal expressions.	✅ ☑️	🔧	💡
no-useless-undefined	Disallow useless `undefined`.	✅ ☑️	🔧	💡
no-zero-fractions	Disallow number literals with zero fractions or dangling dots.	✅ ☑️	🔧
number-literal-case	Enforce proper case for numeric literals.	✅ ☑️	🔧
numeric-separators-style	Enforce the style of numeric separators by correctly grouping digits.	✅ ☑️	🔧
prefer-add-event-listener	Prefer `.addEventListener()` and `.removeEventListener()` over `on`-functions.	✅ ☑️	🔧
prefer-add-event-listener-options	Prefer an options object over a boolean in `.addEventListener()`.	✅ ☑️	🔧
prefer-array-find	Prefer `.find(…)` and `.findLast(…)` over the first or last element from `.filter(…)`.	✅ ☑️	🔧	💡
prefer-array-flat	Prefer `Array#flat()` over legacy techniques to flatten arrays.	✅ ☑️	🔧
prefer-array-flat-map	Prefer `.flatMap(…)` over `.map(…).flat()` and `.filter(…).flatMap(…)`.	✅ ☑️	🔧	💡
prefer-array-from-map	Prefer using the `Array.from()` mapping function argument.	✅ ☑️	🔧	💡
prefer-array-index-of	Prefer `Array#{indexOf,lastIndexOf}()` over `Array#{findIndex,findLastIndex}()` when looking for the index of an item.	✅ ☑️	🔧	💡
prefer-array-last-methods	Prefer last-oriented array methods over `Array#reverse()` or `Array#toReversed()` followed by a method.	✅ ☑️		💡
prefer-array-some	Prefer `.some(…)` over `.filter(…).length` check and `.{find,findLast,findIndex,findLastIndex}(…)`.	✅ ☑️	🔧	💡
prefer-at	Prefer `.at()` method for index access and `String#charAt()`.	✅ ☑️	🔧	💡
prefer-await	Prefer `await` over promise chaining.	✅ ☑️
prefer-bigint-literals	Prefer `BigInt` literals over the constructor.	✅ ☑️	🔧	💡
prefer-blob-reading-methods	Prefer `Blob#arrayBuffer()` over `FileReader#readAsArrayBuffer(…)` and `Blob#text()` over `FileReader#readAsText(…)`.	✅ ☑️
prefer-class-fields	Prefer class field declarations over `this` assignments in constructors.	✅ ☑️	🔧	💡
prefer-classlist-toggle	Prefer using `Element#classList.toggle()` to toggle class names.	✅ ☑️	🔧	💡
prefer-code-point	Prefer `String#codePointAt(…)` over `String#charCodeAt(…)` and `String.fromCodePoint(…)` over `String.fromCharCode(…)`.	✅ ☑️		💡
prefer-date-now	Prefer `Date.now()` to get the number of milliseconds since the Unix Epoch.	✅ ☑️	🔧
prefer-default-parameters	Prefer default parameters over reassignment.	✅ ☑️		💡
prefer-direct-iteration	Prefer direct iteration over default iterator method calls.	✅ ☑️	🔧
prefer-dispose	Prefer using `using`/`await using` over manual `try`/`finally` resource disposal.			💡
prefer-dom-node-append	Prefer `Element#append()` over `Node#appendChild()`.	✅ ☑️	🔧
prefer-dom-node-html-methods	Prefer `.getHTML()` and `.setHTML()` over `.innerHTML`.		🔧	💡
prefer-dom-node-remove	Prefer `childNode.remove()` over `parentNode.removeChild(childNode)`.	✅ ☑️	🔧	💡
prefer-dom-node-text-content	Prefer `.textContent` over `.innerText`.	✅ ☑️		💡
prefer-early-return	Prefer early returns over full-function conditional wrapping.	✅ ☑️	🔧	💡
prefer-event-target	Prefer `EventTarget` over `EventEmitter`.	✅ ☑️
prefer-export-from	Prefer `export…from` when re-exporting.	✅	🔧	💡
prefer-get-or-insert-computed	Prefer `.getOrInsertComputed()` when the default value has side effects.	✅	🔧
prefer-global-number-constants	Prefer global numeric constants over `Number` static properties.	✅ ☑️	🔧
prefer-global-this	Prefer `globalThis` over `window`, `self`, and `global`.	✅ ☑️	🔧
prefer-https	Prefer HTTPS over HTTP.	✅	🔧
prefer-identifier-import-export-specifiers	Prefer identifiers over string literals in import and export specifiers.	✅ ☑️	🔧
prefer-import-meta-properties	Prefer `import.meta.{dirname,filename}` over legacy techniques for getting file paths.		🔧
prefer-includes	Prefer `.includes()` over `.indexOf()`, `.lastIndexOf()`, and `Array#some()` when checking for existence or non-existence.	✅ ☑️	🔧	💡
prefer-includes-over-repeated-comparisons	Prefer `.includes()` over repeated equality comparisons.	✅
prefer-iterable-in-constructor	Prefer passing iterables directly to constructors instead of filling empty collections.	✅ ☑️	🔧
prefer-iterator-concat	Prefer `Iterator.concat(…)` over temporary spread arrays.		🔧	💡
prefer-iterator-to-array	Prefer `Iterator#toArray()` over temporary arrays from iterator spreads.	✅	🔧	💡
prefer-iterator-to-array-at-end	Prefer moving `.toArray()` to the end of iterator helper chains.	✅ ☑️		💡
prefer-keyboard-event-key	Prefer `KeyboardEvent#key` over deprecated keyboard event properties.	✅ ☑️	🔧	💡
prefer-location-assign	Prefer `location.assign()` over assigning to `location.href`.	✅	🔧
prefer-logical-operator-over-ternary	Prefer using a logical operator over a ternary.	✅ ☑️		💡
prefer-math-abs	Prefer `Math.abs()` over manual absolute value expressions and symmetric range checks.	✅ ☑️	🔧
prefer-math-min-max	Prefer `Math.min()` and `Math.max()` over ternaries for simple comparisons.	✅ ☑️	🔧
prefer-math-trunc	Prefer `Math.trunc()` for truncating numbers.	✅ ☑️	🔧	💡
prefer-minimal-ternary	Prefer moving ternaries into the minimal varying part of an expression.	✅ ☑️
prefer-modern-dom-apis	Prefer modern DOM APIs.	✅ ☑️	🔧
prefer-modern-math-apis	Prefer modern `Math` APIs over legacy patterns.	✅ ☑️	🔧
prefer-module	Prefer JavaScript modules (ESM) over CommonJS.	✅ ☑️	🔧	💡
prefer-native-coercion-functions	Prefer using `String`, `Number`, `BigInt`, `Boolean`, and `Symbol` directly.	✅ ☑️	🔧
prefer-negative-index	Prefer negative index over `.length - index` when possible.	✅ ☑️	🔧
prefer-node-protocol	Prefer using the `node:` protocol when importing Node.js builtin modules.	✅ ☑️	🔧
prefer-number-coercion	Prefer `Number()` over `parseFloat()` and base-10 `parseInt()`.	✅ ☑️		💡
prefer-number-is-safe-integer	Prefer `Number.isSafeInteger()` over integer checks.	✅		💡
prefer-number-properties	Prefer `Number` static methods over global functions and optionally static properties over global constants.	✅ ☑️	🔧	💡
prefer-object-define-properties	Prefer `Object.defineProperties()` over multiple `Object.defineProperty()` calls.	✅ ☑️	🔧
prefer-object-destructuring-defaults	Prefer object destructuring defaults over default object literals with spread.	✅		💡
prefer-object-from-entries	Prefer using `Object.fromEntries(…)` to transform a list of key-value pairs into an object.	✅ ☑️	🔧
prefer-object-iterable-methods	Prefer the most specific `Object` iterable method.	✅ ☑️	🔧
prefer-optional-catch-binding	Prefer omitting the `catch` binding parameter.	✅ ☑️	🔧
prefer-path2d	Prefer `Path2D` for repeatedly drawn canvas paths.	✅ ☑️
prefer-private-class-fields	Prefer private class fields over the underscore-prefix convention.	✅	🔧
prefer-prototype-methods	Prefer borrowing methods from the prototype instead of the instance.	✅ ☑️	🔧
prefer-query-selector	Prefer `.querySelector()` and `.querySelectorAll()` over older DOM query methods.	✅	🔧
prefer-queue-microtask	Prefer `queueMicrotask()` over `process.nextTick()`, `setImmediate()`, and `setTimeout(…, 0)`.	✅ ☑️	🔧
prefer-reflect-apply	Prefer `Reflect.apply()` over `Function#apply()`.	✅ ☑️	🔧
prefer-regexp-test	Prefer `RegExp#test()` over `String#match()`, `String#search()`, and `RegExp#exec()`.	✅ ☑️	🔧	💡
prefer-response-static-json	Prefer `Response.json()` over `new Response(JSON.stringify())`.	✅ ☑️	🔧
prefer-scoped-selector	Prefer `:scope` when using element query selector methods.	✅		💡
prefer-set-has	Prefer `Set#has()` over `Array#includes()` when checking for existence or non-existence.	✅ ☑️	🔧	💡
prefer-set-size	Prefer using `Set#size` instead of `Array#length`.	✅ ☑️	🔧
prefer-short-arrow-method	Prefer arrow function properties over methods with a single return.	✅	🔧
prefer-simple-condition-first	Prefer simple conditions first in logical expressions.	✅ ☑️	🔧	💡
prefer-simple-sort-comparator	Prefer a simple comparison function for `Array#sort()`.	✅ ☑️		💡
prefer-single-array-predicate	Prefer a single `Array#some()` or `Array#every()` with a combined predicate.	✅ ☑️		💡
prefer-single-call	Enforce combining multiple `Array#{push,unshift}()`, `Element#classList.{add,remove}()`, and `importScripts()` into one call.	✅ ☑️	🔧	💡
prefer-single-object-destructuring	Prefer a single object destructuring declaration per local const source.	✅	🔧
prefer-smaller-scope	Prefer declaring variables in the smallest possible scope.	✅	🔧
prefer-split-limit	Prefer `String#split()` with a limit.	✅ ☑️	🔧
prefer-spread	Prefer the spread operator over `Array.from(…)`, `Array#concat(…)`, `Array#{slice,toSpliced}()`, and trivial `for…of` copies.	✅	🔧	💡
prefer-string-match-all	Prefer `String#matchAll()` over `RegExp#exec()` loops.	✅ ☑️	🔧
prefer-string-pad-start-end	Prefer `String#padStart()` and `String#padEnd()` over manual string padding.	✅ ☑️	🔧	💡
prefer-string-raw	Prefer using the `String.raw` tag to avoid escaping `\`.	✅ ☑️	🔧
prefer-string-repeat	Prefer `String#repeat()` for repeated whitespace.	✅ ☑️	🔧
prefer-string-replace-all	Prefer `String#replaceAll()` over regex searches with the global flag and `String#split().join()`.	✅ ☑️	🔧
prefer-string-slice	Prefer `String#slice()` over `String#substr()` and `String#substring()`.	✅ ☑️	🔧
prefer-string-starts-ends-with	Prefer `String#startsWith()` & `String#endsWith()` over `RegExp#test()` and `String#indexOf() === 0`.	✅ ☑️	🔧	💡
prefer-string-trim-start-end	Prefer `String#trimStart()` / `String#trimEnd()` over `String#trimLeft()` / `String#trimRight()`.	✅ ☑️	🔧
prefer-structured-clone	Prefer using `structuredClone` to create a deep clone.	✅ ☑️		💡
prefer-switch	Prefer `switch` over multiple `else-if`.	✅ ☑️	🔧
prefer-temporal	Prefer `Temporal` over `Date`.		🔧	💡
prefer-ternary	Prefer ternary expressions over simple `if-else` statements that return or assign values.	✅ ☑️	🔧	💡
prefer-top-level-await	Prefer top-level await over top-level promises and async function calls.	✅ ☑️		💡
prefer-type-error	Enforce throwing `TypeError` in type checking conditions.	✅ ☑️	🔧
prefer-type-literal-last	Require type literals to be last in union and intersection types.	✅ ☑️	🔧
prefer-uint8array-base64	Prefer `Uint8Array#toBase64()` and `Uint8Array.fromBase64()` over `atob()`, `btoa()`, and `Buffer` base64 conversions.	✅ ☑️		💡
prefer-unicode-code-point-escapes	Prefer Unicode code point escapes over legacy escape sequences.	✅ ☑️	🔧	💡
prefer-url-href	Prefer `URL#href` over stringifying a `URL`.	✅ ☑️	🔧
prevent-abbreviations	Prevent abbreviations.	✅	🔧	💡
relative-url-style	Enforce consistent relative URL style.	✅ ☑️	🔧	💡
require-array-join-separator	Enforce using the separator argument with `Array#join()`.	✅ ☑️	🔧
require-array-sort-compare	Require a compare function when calling `Array#sort()` or `Array#toSorted()`.	✅ ☑️		💡
require-css-escape	Require `CSS.escape()` for interpolated values in CSS selectors.	✅ ☑️	🔧
require-module-attributes	Require non-empty module attributes for imports and exports	✅ ☑️	🔧
require-module-specifiers	Require non-empty specifier list in import and export statements.	✅ ☑️	🔧	💡
require-number-to-fixed-digits-argument	Enforce using the digits argument with `Number#toFixed()`.	✅ ☑️	🔧
require-passive-events	Require passive event listeners for high-frequency events.	✅ ☑️	🔧
require-post-message-target-origin	Enforce using the `targetOrigin` argument with `window.postMessage()`.			💡
require-proxy-trap-boolean-return	Require boolean-returning Proxy traps to return booleans.	✅ ☑️	🔧
string-content	Enforce better string content.		🔧	💡
switch-case-braces	Enforce consistent brace style for `case` clauses.	✅	🔧
switch-case-break-position	Enforce consistent `break`/`return`/`continue`/`throw` position in `case` clauses.	✅	🔧
template-indent	Fix whitespace-insensitive template indentation.	✅	🔧
text-encoding-identifier-case	Enforce consistent case for text encoding identifiers.	✅ ☑️	🔧	💡
throw-new-error	Require `new` when creating an error.	✅ ☑️	🔧
try-complexity	Limit the complexity of `try` blocks.

Non-JavaScript files

While most rules target JavaScript and TypeScript, some also lint other file types when used with the corresponding ESLint language plugin such as @eslint/css, @eslint/json, @eslint/markdown, or @html-eslint/eslint-plugin. Each such rule declares this with the meta.languages field.

These rules work on any file type:

These rules also work on specific non-JavaScript languages:

Name	CSS	HTML	JSON	Markdown
`expiring-todo-comments`	✅	✅	✅	✅
`no-empty-file`	✅	✅	✅	✅
`no-invalid-file-input-accept`		✅
`no-manually-wrapped-comments`			✅
`text-encoding-identifier-case`	✅	✅

Deleted and deprecated rules

See the list.

Preset configs

See the ESLint docs for more information about extending config files.

Note: Preset configs will also enable the correct language options.

Recommended config

This plugin exports a recommended config that enforces good practices.

import eslintPluginUnicorn from 'eslint-plugin-unicorn';

export default [
	// …
	eslintPluginUnicorn.configs.recommended,
	{
		rules: {
			'unicorn/prefer-module': 'warn',
		},
	},
];

All config

This plugin exports an all config that enables every rule, except deprecated ones.

import eslintPluginUnicorn from 'eslint-plugin-unicorn';

export default [
	// …
	eslintPluginUnicorn.configs.all,
	{
		rules: {
			'unicorn/prefer-module': 'warn',
		},
	},
];

eslint-plugin-unicorn

eslint-plugin-unicorn

Install

Usage

Rules

Non-JavaScript files

Deleted and deprecated rules

Preset configs

Recommended config

All config

Maintainers

Readme

Keywords