Contents

• About
• Features
• Installation
• Documentation
  • Tree
  • Import
  • Methods
  • Recommended use
  • Types
  • Rules

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?)

rulint/types
│
├── type ESLintConfig
└── 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	rulint_options	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-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-nullish	Enforce .nullish() instead of combining .optional() and .nullable().
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.