From da5ba54087fca4cfdc2c43436bc723faf29da811 Mon Sep 17 00:00:00 2001
From: zanminkian <hellozmj@qq.com>
Date: Mon, 17 Apr 2023 11:37:03 +0000
Subject: [PATCH] feat(plugin): allow some one-line arrow functions

---
 .../src/rules/top-level-function.test.ts      | 25 ++++++++++++++++++-
 .../src/rules/top-level-function.ts           | 11 ++++++++
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/packages/eslint-plugin-antfu/src/rules/top-level-function.test.ts b/packages/eslint-plugin-antfu/src/rules/top-level-function.test.ts
index 06c671b1c5..dc4030ae0e 100644
--- a/packages/eslint-plugin-antfu/src/rules/top-level-function.test.ts
+++ b/packages/eslint-plugin-antfu/src/rules/top-level-function.test.ts
@@ -17,15 +17,38 @@ const valids = [
   // allow export default
   'export default () => {}',
   'export default defineConfig(() => {})',
+  'const foo = (x, y) => x + y',
+  'const foo = (x) => `x: ${x}`',
+  'const foo = () => \'hello\'',
+  'const foo = () => 123',
+  'const foo = () => false',
+  'const foo = () => /abcd/',
+  'const foo = () => undefined',
+  'const foo = () => null',
+  'const foo = () => String(123)',
+  'const foo = async (x, y) => x + y',
+  'const foo = async (x) => `x: ${x}`',
+  'const foo = async () => \'hello\'',
+  'const foo = async () => 123',
+  'const foo = async () => false',
+  'const foo = async () => /abcd/',
+  'const foo = async () => undefined',
+  'const foo = async () => null',
+  'const foo = async () => String(123)',
+  // 'const foo = () => ({a: 123})', // Not sure that one-line object expression is valid
 ]
 
 const invalids = [
+  [
+    'const foo = (x, y) => \nx + y',
+    'function foo (x, y) {\n  return x + y\n}',
+  ],
   [
     'const foo = (as: string, bar: number) => { return as + bar }',
     'function foo (as: string, bar: number) { return as + bar }',
   ],
   [
-    'const foo = <K, T extends Boolean>(as: string, bar: number): Omit<T, K> => as + bar',
+    'const foo = <K, T extends Boolean>(as: string, bar: number): Omit<T, K> => \nas + bar',
     'function foo <K, T extends Boolean>(as: string, bar: number): Omit<T, K> {\n  return as + bar\n}',
   ],
   [
diff --git a/packages/eslint-plugin-antfu/src/rules/top-level-function.ts b/packages/eslint-plugin-antfu/src/rules/top-level-function.ts
index b0ce043038..0120066b26 100644
--- a/packages/eslint-plugin-antfu/src/rules/top-level-function.ts
+++ b/packages/eslint-plugin-antfu/src/rules/top-level-function.ts
@@ -40,6 +40,17 @@ export default createEslintRule<Options, MessageIds>({
           return
         if (declaration.id.typeAnnotation)
           return
+        if (
+          [
+            'BinaryExpression',
+            'Literal',
+            'TemplateLiteral',
+            'Identifier',
+            'CallExpression',
+          ].includes(declaration.init?.body.type)
+          && declaration.id?.loc.start.line === declaration.init?.body.loc.end.line
+        )
+          return
 
         const arrowFn = declaration.init
         const body = declaration.init.body