Contents

• About
• Features
• Installation
• Documentation
  • Tree
  • Import
  • Methods
  • Recommended use
  • Types
  • Rules
• Links
  • Discord
  • Telegram
  • Twitter
  • GitHub
• License

About

Strict ESLint presets for modern TypeScript.

Features

• Enforces type safety
• Prohibits potentially unsafe patterns
• Encourages modern syntax
• Encourages more accurate Zod (eslint-plugin-zod)
• Encourages the use of arrow functions
• Encourages the use of try/catch
• Bans var and warns about proper use of const and let
• Disallows interfaces, using only types
• Requires explicit readonly and accessibility modifiers in classes
• ...and much more!

Installation

You can install it as follows.

ⓘ Note

During installation, these packages are installed automatically: @eslint/js, @types/node, eslint, eslint-plugin-prefer-arrow-functions, eslint-plugin-zod, jiti, typescript, and typescript-eslint.

Therefore, you do not need to install these packages separately. If they are already listed in your project's dependencies, keeping them is unnecessary and they can be safely removed.

# NPM
npm add rulint

# PNPM
pnpm add rulint

# Yarn
yarn add rulint

# Bun
bun add rulint

# Deno
deno add rulint

Documentation

Tree

Briefly as follows.

rulint
│
├── rulint(options?)
│
└── type RulintOptions

Import

Briefly as follows.

📁 ./eslint.config.ts

import { rulint } from 'rulint';

export default rulint();

Methods

rulint(options?)

ESLint configuration generated by Rulint.

Parameter	Type	Default	Description
options?	RulintOptions	RulintOptionsDefault	Rulint options.

returns ESLintConfig[]

Example:

export default rulint();

Recommended use

Suggested uses are as follows. We recommend using Prettier.

📁 ./eslint.config.ts

import { rulint } from 'rulint';

export default rulint();

📁 ./tsconfig.json

{
  "compilerOptions": {
    "strict": true,

    "outDir": "./dist",
    "target": "ESNext",
    "module": "ESNext",
    "moduleResolution": "bundler",
    "lib": ["ESNext", "DOM"],

    "types": ["*"],
    "typeRoots": ["./src/types", "./node_modules/@types"]
  }
}

📁 ./.prettierrc.json

{
  "semi": true,
  "singleQuote": true,

  "printWidth": 1000,
  "tabWidth": 2,

  "trailingComma": "none"
}

Types

Type
ESLintConfig
RulintOptions

Rules

Rulint adds 203 rules to your workspace.

Rule	Description
arrow-body-style	Require braces around arrow function bodies.
curly	Enforce consistent brace style for all control statements.
dot-notation	Enforce dot notation whenever possible.
eqeqeq	Require the use of === and !==.
for-direction	Enforce for loop update clause moving the counter in the right direction.
no-array-constructor	Disallow Array constructors.
no-async-promise-executor	Disallow using an async function as a Promise executor.
no-case-declarations	Disallow lexical declarations in case clauses.
no-compare-neg-zero	Disallow comparing against -0.
no-cond-assign	Disallow assignment operators in conditional expressions.
no-constant-binary-expression	Disallow expressions where the operation doesn't affect the value.
no-constant-condition	Disallow constant expressions in conditions.
no-control-regex	Disallow control characters in regular expressions.
no-debugger	Disallow the use of debugger.
no-delete-var	Disallow deleting variables.
no-dupe-else-if	Disallow duplicate conditions in if-else-if chains.
no-duplicate-case	Disallow duplicate case labels.
no-duplicate-imports	Disallow duplicate module imports.
no-empty-character-class	Disallow empty character classes in regular expressions.
no-empty-function	Disallow empty functions.
no-empty-pattern	Disallow empty destructuring patterns.
no-empty-static-block	Disallow empty static blocks.
no-empty	Disallow empty block statements.
no-eval	Disallow the use of eval().
no-ex-assign	Disallow reassigning exceptions in catch clauses.
no-extra-boolean-cast	Disallow unnecessary boolean casts.
no-fallthrough	Disallow fallthrough of case statements.
no-global-assign	Disallow assignments to native objects or read-only global variables.
no-implied-eval	Disallow the use of eval()-like methods.
no-invalid-regexp	Disallow invalid regular expression strings in RegExp constructors.
no-irregular-whitespace	Disallow irregular whitespace.
no-loss-of-precision	Disallow literal numbers that lose precision.
no-misleading-character-class	Disallow characters which are made with multiple code points in character class syntax.
no-new-func	Disallow new operators with the Function object.
no-new-wrappers	Disallow new operators with the String, Number, and Boolean objects.
no-nonoctal-decimal-escape	Disallow \8 and \9 escape sequences in string literals.
no-object-constructor	Disallow calls to the Object constructor without an argument.
no-octal	Disallow octal literals.
no-prototype-builtins	Disallow calling some Object.prototype methods directly on objects.
no-regex-spaces	Disallow multiple spaces in regular expressions.
no-restricted-imports	Disallow specified modules when loaded by import.
no-restricted-syntax	Disallow specified syntax.
no-return-await	Disallow unnecessary return await.
no-self-assign	Disallow assignments where both sides are exactly the same.
no-shadow-restricted-names	Disallow identifiers from shadowing restricted names.
no-sparse-arrays	Disallow sparse arrays.
no-throw-literal	Disallow throwing literals as exceptions.
no-unassigned-vars	Disallow let or var variables that are read but never assigned.
no-unexpected-multiline	Disallow confusing multiline expressions.
no-unsafe-finally	Disallow control flow statements in finally blocks.
no-unsafe-optional-chaining	Disallow use of optional chaining in contexts where the undefined value is not allowed.
no-unused-expressions	Disallow unused expressions.
no-unused-labels	Disallow unused labels.
no-unused-private-class-members	Disallow unused private class members.
no-unused-vars	Disallow unused variables.
no-useless-assignment	Disallow variable assignments when the value is not used.
no-useless-backreference	Disallow useless backreferences in regular expressions.
no-useless-call	Disallow unnecessary calls to .call() and .apply().
no-useless-catch	Disallow unnecessary catch clauses.
no-useless-computed-key	Disallow unnecessary computed property keys in objects and classes.
no-useless-concat	Disallow unnecessary concatenation of literals or template literals.
no-useless-constructor	Disallow unnecessary constructors.
no-useless-escape	Disallow unnecessary escape characters.
no-useless-rename	Disallow renaming import, export, and destructured assignments to the same name.
no-useless-return	Disallow redundant return statements.
no-var	Require let or const instead of var.
object-shorthand	Require or disallow method and property shorthand syntax for object literals.
one-var	Enforce variables to be declared either together or separately in functions.
prefer-const	Require const declarations for variables that are never reassigned after declared.
prefer-promise-reject-errors	Require using Error objects as Promise rejection reasons.
prefer-rest-params	Require rest parameters instead of arguments.
prefer-spread	Require spread operators instead of .apply().
prefer-template	Require template literals instead of string concatenation.
preserve-caught-error	Disallow losing originally caught error when re-throwing custom errors.
require-await	Disallow async functions which have no await expression.
require-yield	Require generator functions to contain yield.
use-isnan	Require calls to isNaN() when checking for NaN.
valid-typeof	Enforce comparing typeof expressions against valid strings.
@typescript-eslint/adjacent-overload-signatures	Require that function overload signatures be consecutive.
@typescript-eslint/array-type	Require consistently using either T[] or Array<T> for arrays.
@typescript-eslint/await-thenable	Disallow awaiting a value that is not a Thenable.
@typescript-eslint/ban-ts-comment	Disallow @ts-<directive> comments or require descriptions after directives.
@typescript-eslint/ban-tslint-comment	Disallow // tslint:<rule-flag> comments.
@typescript-eslint/class-literal-property-style	Enforce that literals on classes are exposed in a consistent style.
@typescript-eslint/consistent-generic-constructors	Enforce specifying generic type arguments on type annotation or constructor name of a constructor call.
@typescript-eslint/consistent-indexed-object-style	Require or disallow the Record type.
@typescript-eslint/consistent-type-assertions	Enforce consistent usage of type assertions.
@typescript-eslint/consistent-type-definitions	Enforce type definitions to consistently use either interface or type.
@typescript-eslint/consistent-type-exports	Enforce consistent usage of type exports.
@typescript-eslint/consistent-type-imports	Enforce consistent usage of type imports.
@typescript-eslint/dot-notation	Enforce dot notation whenever possible.
@typescript-eslint/explicit-member-accessibility	Require explicit accessibility modifiers on class properties and methods.
@typescript-eslint/no-array-constructor	Disallow generic Array constructors.
@typescript-eslint/no-array-delete	Disallow using the delete operator on array values.
@typescript-eslint/no-base-to-string	Require .toString() and .toLocaleString() to only be called on objects which provide useful information when stringified.
@typescript-eslint/no-confusing-non-null-assertion	Disallow non-null assertion in locations that may be confusing.
@typescript-eslint/no-confusing-void-expression	Require expressions of type void to appear in statement position.
@typescript-eslint/no-deprecated	Disallow using code marked as @deprecated.
@typescript-eslint/no-duplicate-enum-values	Disallow duplicate enum member values.
@typescript-eslint/no-duplicate-type-constituents	Disallow duplicate constituents of union or intersection types.
@typescript-eslint/no-dynamic-delete	Disallow using the delete operator on computed key expressions.
@typescript-eslint/no-empty-function	Disallow empty functions.
@typescript-eslint/no-empty-object-type	Disallow accidentally using the "empty object" type.
@typescript-eslint/no-explicit-any	Disallow the any type.
@typescript-eslint/no-extra-non-null-assertion	Disallow extra non-null assertions.
@typescript-eslint/no-extraneous-class	Disallow classes used as namespaces.
@typescript-eslint/no-floating-promises	Require Promise-like statements to be handled appropriately.
@typescript-eslint/no-for-in-array	Disallow iterating over an array with a for-in loop.
@typescript-eslint/no-implied-eval	Disallow the use of eval()-like functions.
@typescript-eslint/no-inferrable-types	Disallow explicit type declarations for variables or parameters initialized to a number, string, or boolean.
@typescript-eslint/no-invalid-void-type	Disallow void type outside of generic or return types.
@typescript-eslint/no-meaningless-void-operator	Disallow the void operator except when used to discard a value.
@typescript-eslint/no-misused-new	Enforce valid definition of new and constructor.
@typescript-eslint/no-misused-promises	Disallow Promises in places not designed to handle them.
@typescript-eslint/no-misused-spread	Disallow using the spread operator when it might cause unexpected behavior.
@typescript-eslint/no-mixed-enums	Disallow enums from having both number and string members.
@typescript-eslint/no-namespace	Disallow TypeScript namespaces.
@typescript-eslint/no-non-null-asserted-nullish-coalescing	Disallow non-null assertions in the left operand of a nullish coalescing operator.
@typescript-eslint/no-non-null-asserted-optional-chain	Disallow non-null assertions after an optional chain expression.
@typescript-eslint/no-non-null-assertion	Disallow non-null assertions using the ! postfix operator.
@typescript-eslint/no-redundant-type-constituents	Disallow members of unions and intersections that do nothing or override type information.
@typescript-eslint/no-require-imports	Disallow invocation of require().
@typescript-eslint/no-this-alias	Disallow aliasing this.
@typescript-eslint/no-unnecessary-boolean-literal-compare	Disallow unnecessary equality comparisons against boolean literals.
@typescript-eslint/no-unnecessary-condition	Disallow conditionals where the type is always truthy or always falsy.
@typescript-eslint/no-unnecessary-template-expression	Disallow unnecessary template expressions.
@typescript-eslint/no-unnecessary-type-arguments	Disallow type arguments that are equal to the default.
@typescript-eslint/no-unnecessary-type-assertion	Disallow type assertions that do not change the type of an expression.
@typescript-eslint/no-unnecessary-type-constraint	Disallow unnecessary constraints on generic types.
@typescript-eslint/no-unnecessary-type-conversion	Disallow conversion idioms when they do not change the type or value of the expression.
@typescript-eslint/no-unnecessary-type-parameters	Disallow type parameters that aren't used multiple times.
@typescript-eslint/no-unsafe-argument	Disallow calling a function with a value with type any.
@typescript-eslint/no-unsafe-assignment	Disallow assigning a value with type any to variables and properties.
@typescript-eslint/no-unsafe-call	Disallow calling a value with type any.
@typescript-eslint/no-unsafe-declaration-merging	Disallow unsafe declaration merging.
@typescript-eslint/no-unsafe-enum-comparison	Disallow comparing an enum value with a non-enum value.
@typescript-eslint/no-unsafe-function-type	Disallow using the unsafe built-in Function type.
@typescript-eslint/no-unsafe-member-access	Disallow member access on a value with type any.
@typescript-eslint/no-unsafe-return	Disallow returning a value with type any from a function.
@typescript-eslint/no-unsafe-unary-minus	Require unary negation to take a number.
@typescript-eslint/no-unused-expressions	Disallow unused expressions.
@typescript-eslint/no-unused-vars	Disallow unused variables.
@typescript-eslint/no-useless-constructor	Disallow unnecessary constructors.
@typescript-eslint/no-useless-default-assignment	Disallow default values that will never be used.
@typescript-eslint/no-wrapper-object-types	Disallow using confusing built-in primitive class wrappers.
@typescript-eslint/non-nullable-type-assertion-style	Enforce non-null assertions over explicit type assertions.
@typescript-eslint/only-throw-error	Disallow throwing non-Error values as exceptions.
@typescript-eslint/prefer-as-const	Enforce the use of as const over literal type.
@typescript-eslint/prefer-find	Enforce the use of Array.prototype.find() over Array.prototype.filter() followed by [0] when looking for a single result.
@typescript-eslint/prefer-for-of	Enforce the use of for-of loop over the standard for loop where possible.
@typescript-eslint/prefer-function-type	Enforce using function types instead of interfaces with call signatures.
@typescript-eslint/prefer-includes	Enforce includes method over indexOf method.
@typescript-eslint/prefer-literal-enum-member	Require all enum members to be literal values.
@typescript-eslint/prefer-namespace-keyword	Require using namespace keyword over module keyword to declare custom TypeScript modules.
@typescript-eslint/prefer-nullish-coalescing	Enforce using the nullish coalescing operator instead of logical assignments or chaining.
@typescript-eslint/prefer-optional-chain	Enforce using concise optional chain expressions instead of chained logical ands, negated logical ors, or empty objects.
@typescript-eslint/prefer-promise-reject-errors	Require using Error objects as Promise rejection reasons.
@typescript-eslint/prefer-readonly	Require private members to be marked as readonly if they're never modified outside of the constructor.
@typescript-eslint/prefer-reduce-type-parameter	Enforce using type parameter when calling Array#reduce instead of using a type assertion.
@typescript-eslint/prefer-regexp-exec	Enforce RegExp#exec over String#match if no global flag is provided.
@typescript-eslint/prefer-return-this-type	Enforce that this is used when only this type is returned.
@typescript-eslint/prefer-string-starts-ends-with	Enforce using String#startsWith and String#endsWith over other equivalent methods of checking substrings.
@typescript-eslint/related-getter-setter-pairs	Enforce that get() types should be assignable to their equivalent set() type.
@typescript-eslint/require-await	Disallow async functions which do not return promises and have no await expression.
@typescript-eslint/restrict-plus-operands	Require both operands of addition to be the same type and be bigint, number, or string.
@typescript-eslint/restrict-template-expressions	Enforce template literal expressions to be of string type.
@typescript-eslint/return-await	Enforce consistent awaiting of returned promises.
@typescript-eslint/strict-boolean-expressions	Disallow certain types in boolean expressions.
@typescript-eslint/triple-slash-reference	Disallow certain triple slash directives in favor of ES6-style import declarations.
@typescript-eslint/unbound-method	Enforce unbound methods are called with their expected scope.
@typescript-eslint/unified-signatures	Disallow two overloads that could be unified into one with a union or an optional/rest parameter.
@typescript-eslint/use-unknown-in-catch-callback-variable	Enforce typing arguments in Promise rejection callbacks as unknown.
prefer-arrow-functions/prefer-arrow-functions	Auto-fix plain Functions into Arrow Functions, in all cases where conversion would result in the same behaviour.
zod/array-style	Enforce consistent Zod array style.
zod/consistent-import	Enforce a consistent import style for Zod.
zod/consistent-schema-var-name	Enforce a consistent naming convention for Zod schema variables.
zod/no-any-schema	Disallow usage of z.any() in Zod schemas.
zod/no-coerce-boolean	Disallow z.coerce.boolean() because it treats any non-empty string as true.
zod/no-duplicate-schema-methods	Disallow calling the same schema method more than once in a single chain.
zod/no-empty-custom-schema	Disallow usage of z.custom() without arguments.
zod/no-native-enum	Disallow deprecated z.nativeEnum() in favor of z.enum().
zod/no-number-schema-with-finite	Disallow deprecated z.number().finite(). In Zod 4+ number schemas do not allow infinite values by default, so it is a no-op.
zod/no-number-schema-with-int	Disallow usage of z.number().int() as it is considered legacy.
zod/no-number-schema-with-is-finite	Disallow using deprecated isFinite on a Zod number schema; in v4+ it is always true.
zod/no-number-schema-with-is-int	Disallow using deprecated isInt on a Zod number schema; check the format property instead.
zod/no-number-schema-with-safe	Disallow deprecated z.number().safe(). Use z.int(); .safe() is now identical to .int().
zod/no-number-schema-with-step	Disallow deprecated z.number().step(). Use .multipleOf() instead.
zod/no-optional-and-default-together	Disallow using both .optional() and .default() on the same Zod schema.
zod/no-promise-schema	Disallow deprecated z.promise() schemas.
zod/no-schema-with-is-nullable	Disallow deprecated .isNullable() on a Zod schema; use safeParse(null).success instead.
zod/no-schema-with-is-optional	Disallow deprecated .isOptional() on a Zod schema; use safeParse(undefined).success instead.
zod/no-string-schema-with-uuid	Disallow usage of z.string().uuid() in favor of the dedicated z.uuid() schema.
zod/no-throw-in-refine	Disallow throwing errors directly inside Zod refine callbacks.
zod/prefer-enum-over-literal-union	Prefer z.enum() over z.union() when all members are string literals.
zod/prefer-loose-object	Prefer z.looseObject() over z.object().passthrough() and z.object().loose().
zod/prefer-meta-last	Enforce .meta() as last method.
zod/prefer-meta	Enforce usage of .meta() over .describe().
zod/prefer-strict-object	Prefer z.strictObject() over z.object().strict().
zod/prefer-string-schema-with-trim	Enforce z.string().trim() to prevent accidental leading/trailing whitespace.
zod/prefer-top-level-string-formats	Prefer top-level string format schemas over deprecated z.string().<format>() methods.
zod/prefer-trim-before-string-length-checks	Enforce .trim() is called before string length checks to ensure accurate validation.
zod/require-brand-type-parameter	Require type parameter on .brand() functions.
zod/require-error-message	Enforce that custom refinements include an error message.

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License

MIT License

Copyright (c) 2025 Keift

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.