From 5359120ed3313a3b6bb5355e163c4e9a928ea562 Mon Sep 17 00:00:00 2001
From: chenjiahan <chenjiahan@youzan.com>
Date: Mon, 21 Sep 2020 18:38:33 +0800
Subject: [PATCH] types: improve useParent typing

---
 src/composition/use-relation.ts | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/composition/use-relation.ts b/src/composition/use-relation.ts
index 658deab55..a47778df6 100644
--- a/src/composition/use-relation.ts
+++ b/src/composition/use-relation.ts
@@ -1,11 +1,11 @@
 import { inject, computed, onUnmounted } from 'vue';
 
-export type Parent<T = unknown> = null | {
-  children: T[];
-};
+type Parent = { children: unknown[] };
 
-export function useParent<T = unknown>(key: string, child: T = {} as T) {
-  const parent = inject<Parent<T>>(key, null);
+type Child<T> = T extends { children: (infer U)[] } ? U : never;
+
+export function useParent<P extends Parent>(key: string, child: Child<P>) {
+  const parent = inject<P | null>(key, null);
 
   if (parent) {
     const { children } = parent;