feat(eslint-plugin): [require-types-exports] add new rule

packages/eslint-plugin/docs/rules/require-types-exports.md

@@ -0,0 +1,75 @@
+---
+description: 'Require exporting types that are used in exported functions declarations.'
+---
+
+> 🛑 This file is source code, not the primary documentation location! 🛑
+>
+> See **https://typescript-eslint.io/rules/require-types-exports** for documentation.
+
+When exporting functions from a module, it is recommended to export also all the
+types that are used in the function declarations. This is useful for consumers of
+the module, as it allows them to use the types in their own code without having to
+use things like [`Parameters`](https://www.typescriptlang.org/docs/handbook/utility-types.html#parameterstype)
+or [`ReturnType`](https://www.typescriptlang.org/docs/handbook/utility-types.html#returntypetype) to extract the types from the function.
+
+## Examples
+
+<!--tabs-->
+
+### ❌ Incorrect
+
+```ts
+type Arg = string;
+type Result = number;
+
+export function strLength(arg: Arg): Result {
+  return arg.length;
+}
+
+interface Fruit {
+  name: string;
+  color: string;
+}
+
+export const getFruitName = (fruit: Fruit) => fruit.name;
+
+enum Color {
+  Red = 'red',
+  Green = 'green',
+  Blue = 'blue',
+}
+
+export declare function getRandomColor(): Color;
+```
+
+### ✅ Correct
+
+```ts
+export type Arg = string;
+export type Result = number;
+
+export function strLength(arg: Arg): Result {
+  return arg.length;
+}
+
+export interface Fruit {
+  name: string;
+  color: string;
+}
+
+export const getFruitName = (fruit: Fruit) => fruit.name;
+
+export enum Color {
+  Red = 'red',
+  Green = 'green',
+  Blue = 'blue',
+}
+
+export declare function getRandomColor(): Color;
+```
+
+<!--/tabs-->
+
+## When Not To Use It
+
+When you don't want to enforce exporting types that are used in exported functions declarations.

packages/eslint-plugin/src/configs/all.ts

@@ -142,6 +142,7 @@ export = {
     '@typescript-eslint/require-array-sort-compare': 'error',
     'require-await': 'off',
     '@typescript-eslint/require-await': 'error',
+    '@typescript-eslint/require-types-exports': 'error',
     '@typescript-eslint/restrict-plus-operands': 'error',
     '@typescript-eslint/restrict-template-expressions': 'error',
     'no-return-await': 'off',

packages/eslint-plugin/src/configs/disable-type-checked.ts

@@ -55,6 +55,7 @@ export = {
     '@typescript-eslint/promise-function-async': 'off',
     '@typescript-eslint/require-array-sort-compare': 'off',
     '@typescript-eslint/require-await': 'off',
+    '@typescript-eslint/require-types-exports': 'off',
     '@typescript-eslint/restrict-plus-operands': 'off',
     '@typescript-eslint/restrict-template-expressions': 'off',
     '@typescript-eslint/return-await': 'off',

packages/eslint-plugin/src/configs/strict-type-checked.ts

@@ -71,6 +71,7 @@ export = {
     '@typescript-eslint/prefer-ts-expect-error': 'error',
     'require-await': 'off',
     '@typescript-eslint/require-await': 'error',
+    '@typescript-eslint/require-types-exports': 'error',
     '@typescript-eslint/restrict-plus-operands': 'error',
     '@typescript-eslint/restrict-template-expressions': 'error',
     '@typescript-eslint/triple-slash-reference': 'error',

packages/eslint-plugin/src/rules/index.ts

@@ -125,6 +125,7 @@ import promiseFunctionAsync from './promise-function-async';
 import quotes from './quotes';
 import requireArraySortCompare from './require-array-sort-compare';
 import requireAwait from './require-await';
+import requireTypesExports from './require-types-exports';
 import restrictPlusOperands from './restrict-plus-operands';
 import restrictTemplateExpressions from './restrict-template-expressions';
 import returnAwait from './return-await';
@@ -267,6 +268,7 @@ export default {
   quotes: quotes,
   'require-array-sort-compare': requireArraySortCompare,
   'require-await': requireAwait,
+  'require-types-exports': requireTypesExports,
   'restrict-plus-operands': restrictPlusOperands,
   'restrict-template-expressions': restrictTemplateExpressions,
   'return-await': returnAwait,