Add rule @typescript-eslint/explicit-function-return-type

Author: Shinigami92

src/rules/typescript-eslint/explicit-function-return-type.d.ts

@@ -0,0 +1,63 @@
+import type { RuleConfig } from '../rule-config';
+
+/**
+ * Option.
+ */
+export type ExplicitFunctionReturnTypeOption = {
+  /**
+   * If `true`, only functions which are part of a declaration will be checked.
+   *
+   * @default false
+   */
+  allowExpressions?: boolean;
+  /**
+   * If `true`, type annotations are also allowed on the variable of a function expression rather than on the function directly.
+   *
+   * @default true
+   */
+  allowTypedFunctionExpressions?: boolean;
+  /**
+   * If `true`, functions immediately returning another function expression will not be checked.
+   *
+   * @default true
+   */
+  allowHigherOrderFunctions?: boolean;
+  /**
+   * If `true`, arrow functions immediately returning a `as const` value will not be checked.
+   *
+   * @default true
+   */
+  allowDirectConstAssertionInArrowFunctions?: boolean;
+  /**
+   * If `true`, concise arrow functions that start with the void keyword will not be checked.
+   *
+   * @default false
+   */
+  allowConciseArrowFunctionExpressionsStartingWithVoid?: boolean;
+};
+
+/**
+ * Options.
+ */
+export type ExplicitFunctionReturnTypeOptions = [ExplicitFunctionReturnTypeOption?];
+
+/**
+ * Require explicit return types on functions and class methods.
+ *
+ * @see [explicit-function-return-type](https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/explicit-function-return-type.md)
+ */
+export type ExplicitFunctionReturnTypeRuleConfig = RuleConfig<ExplicitFunctionReturnTypeOptions>;
+
+/**
+ * Require explicit return types on functions and class methods.
+ *
+ * @see [explicit-function-return-type](https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/explicit-function-return-type.md)
+ */
+export interface ExplicitFunctionReturnTypeRule {
+  /**
+   * Require explicit return types on functions and class methods.
+   *
+   * @see [explicit-function-return-type](https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/explicit-function-return-type.md)
+   */
+  '@typescript-eslint/explicit-function-return-type': ExplicitFunctionReturnTypeRuleConfig;
+}

src/rules/typescript-eslint/index.d.ts

@@ -1,6 +1,7 @@
 import type { BanTsCommentRule } from './ban-ts-comment';
+import type { ExplicitFunctionReturnTypeRule } from './explicit-function-return-type';
 
 /**
  * All @typescript-eslint rules.
  */
-export type TypeScriptEslintRules = BanTsCommentRule;
+export type TypeScriptEslintRules = BanTsCommentRule & ExplicitFunctionReturnTypeRule;