#ban-types

#Configuration

import { defineConfig, ts } from '@rslint/core';

export default defineConfig([
  ts.configs.recommended,
  {
    rules: {
      '@typescript-eslint/ban-types': 'error',
    },
  },
]);

#Rule Details

Disallow certain types. Some built-in TypeScript types like String, Boolean, Number, Symbol, BigInt, Object, Function, and {} are almost always mistakes when used as types. This rule bans these problematic types and suggests preferred alternatives.

The default banned types include the uppercase wrapper types (String -> string, Boolean -> boolean, etc.) as well as Function, Object, and {}. Custom types can be added or defaults can be overridden.

Examples of incorrect code for this rule:

const str: String = 'hello';
const num: Number = 42;
const obj: Object = {};
const fn: Function = () => {};

Examples of correct code for this rule:

const str: string = 'hello';
const num: number = 42;
const obj: object = {};
const fn: () => void = () => {};

#Original Documentation

• typescript-eslint ban-types