From fe2b27ffb98932ec8e822bd88b4de1666810521c Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Thu, 10 Jan 2019 22:44:55 -0500
Subject: [PATCH] types: typing for Vue.observable

---
 flow/global-api.js           | 2 ++
 src/core/global-api/index.js | 2 +-
 types/test/vue-test.ts       | 3 +++
 types/vue.d.ts               | 2 ++
 4 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/flow/global-api.js b/flow/global-api.js
index eab244c2..0ce54fda 100644
--- a/flow/global-api.js
+++ b/flow/global-api.js
@@ -16,6 +16,8 @@ declare interface GlobalAPI {
   component: (id: string, def?: Class<Component> | Object) => Class<Component>;
   filter: (id: string, def?: Function) => Function | void;
 
+  observable: <T>(value: T) => T;
+
   // allow dynamic method registration
   [key: string]: any
 };
diff --git a/src/core/global-api/index.js b/src/core/global-api/index.js
index 2bca92bb..b3387a89 100644
--- a/src/core/global-api/index.js
+++ b/src/core/global-api/index.js
@@ -46,7 +46,7 @@ export function initGlobalAPI (Vue: GlobalAPI) {
   Vue.nextTick = nextTick
 
   // 2.6 explicit observable API
-  Vue.observable = (obj: any): any => {
+  Vue.observable = <T>(obj: T): T => {
     observe(obj)
     return obj
   }
diff --git a/types/test/vue-test.ts b/types/test/vue-test.ts
index 40ded2d2..57cafc47 100644
--- a/types/test/vue-test.ts
+++ b/types/test/vue-test.ts
@@ -200,3 +200,6 @@ declare function decorate<VC extends typeof Vue>(v: VC): VC;
 class Decorated extends Vue {
   a = 123;
 }
+
+const obj = Vue.observable({ a: 1 })
+obj.a++
diff --git a/types/vue.d.ts b/types/vue.d.ts
index 2098a694..1b92e666 100644
--- a/types/vue.d.ts
+++ b/types/vue.d.ts
@@ -119,6 +119,8 @@ export interface VueConstructor<V extends Vue = Vue> {
     staticRenderFns: (() => VNode)[];
   };
 
+  observable<T>(obj: T): T;
+
   config: VueConfiguration;
 }