Contents

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