From 264cc707136cb854527b0d6a4c9956b1db11a423 Mon Sep 17 00:00:00 2001
From: Masa-Shin <34234442+Masa-Shin@users.noreply.github.com>
Date: Thu, 23 Jun 2022 02:59:52 +0900
Subject: [PATCH] Improve type definition (#92)

---
 index.d.ts      | 40 +++++++++++++++++++++++-----------------
 index.test-d.ts | 30 +++++++++++++++++++++++++++++-
 2 files changed, 52 insertions(+), 18 deletions(-)

diff --git a/index.d.ts b/index.d.ts
index e1e9416..f4ee3c3 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -45,13 +45,16 @@ export type CamelCaseKeys<
 > = T extends readonly any[]
 	// Handle arrays or tuples.
 	? {
-		[P in keyof T]: CamelCaseKeys<
-		T[P],
-		Deep,
-		IsPascalCase,
-		Exclude,
-		StopPaths
-		>;
+		// eslint-disable-next-line @typescript-eslint/ban-types
+		[P in keyof T]: {} extends CamelCaseKeys<T[P]>
+			? T[P]
+			: CamelCaseKeys<
+			T[P],
+			Deep,
+			IsPascalCase,
+			Exclude,
+			StopPaths
+			>;
 	}
 	: T extends Record<string, any>
 		// Handle objects.
@@ -64,16 +67,19 @@ export type CamelCaseKeys<
 				true,
 			]
 				? T[P]
-				: [Deep] extends [true]
-					? CamelCaseKeys<
-					T[P],
-					Deep,
-					IsPascalCase,
-					Exclude,
-					StopPaths,
-					AppendPath<Path, P & string>
-					>
-					: T[P];
+				// eslint-disable-next-line @typescript-eslint/ban-types
+				: {} extends CamelCaseKeys<T[P]>
+					? T[P]
+					: [Deep] extends [true]
+						? CamelCaseKeys<
+						T[P],
+						Deep,
+						IsPascalCase,
+						Exclude,
+						StopPaths,
+						AppendPath<Path, P & string>
+						>
+						: T[P];
 		}
 		// Return anything else as-is.
 		: T;
diff --git a/index.test-d.ts b/index.test-d.ts
index f2b2f99..6017f4d 100644
--- a/index.test-d.ts
+++ b/index.test-d.ts
@@ -1,4 +1,4 @@
-/* eslint-disable @typescript-eslint/naming-convention */
+/* eslint-disable @typescript-eslint/naming-convention, @typescript-eslint/indent */
 import {expectType, expectAssignable, expectNotType} from 'tsd';
 import camelcaseKeys, {type CamelCaseKeys} from './index.js';
 
@@ -350,3 +350,31 @@ expectNotType<InvalidConvertedExcludeObjectDataType>(
 		exclude,
 	}),
 );
+
+expectType<{
+	funcFoo: () => 'foo';
+	recordBar: {foo: string};
+	promiseBaz: Promise<unknown>;
+}>(
+	camelcaseKeys({
+		func_foo: () => 'foo',
+		record_bar: {foo: 'bar'},
+		promise_baz: new Promise(resolve => {
+			resolve(true);
+		}),
+	}),
+);
+
+expectType<[
+	() => 'foo',
+	{foo: string},
+	Promise<unknown>,
+]>(
+	camelcaseKeys([
+		() => 'foo',
+		{foo: 'bar'},
+		new Promise(resolve => {
+			resolve(true);
+		}),
+	]),
+);