From d6b81d0c7134e7499d633b8c96e9c319f413d51f Mon Sep 17 00:00:00 2001
From: nighca <nighca@live.cn>
Date: Tue, 19 Sep 2017 16:32:26 +0800
Subject: [PATCH] surpport fromMobx fields used in vue computed & watch

---
 src/install.ts | 32 ++++++++++++++++++++--------
 test/index.ts  | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 81 insertions(+), 9 deletions(-)

diff --git a/src/install.ts b/src/install.ts
index b3461fa..6164c15 100644
--- a/src/install.ts
+++ b/src/install.ts
@@ -11,25 +11,27 @@ export default function install(Vue: typeof VueClass, mobxMethods: IMobxMethods)
 
   const defineReactive = (Vue as any).util.defineReactive
 
+  function beforeCreate(this: VueClass) {
+    const vm = this
+    getFromStoreEntries(vm).forEach(({ key, compute }) => {
+      defineReactive(vm, key, null)
+    })
+  }
+
   function created(this: VueClass) {
     const vm = this
-    const fromStore = vm.$options[optionName]
-    if (!fromStore) {
+    const entries = getFromStoreEntries(vm)
+    if (entries.length <= 0) {
       return
     }
 
     const disposers: Disposer[] = vm[disposersName] = []
 
-    Object.keys(fromStore).forEach(key => {
-      const compute = fromStore[key]
+    entries.forEach(({ key, compute }) => {
       disposers.push(mobxMethods.reaction(
         () => compute.apply(vm),
         val => {
-          if (key in vm) {
-            vm[key] = val
-          } else {
-            defineReactive(vm, key, val)
-          }
+          vm[key] = val
         },
         true
       ))
@@ -47,7 +49,19 @@ export default function install(Vue: typeof VueClass, mobxMethods: IMobxMethods)
   }
 
   Vue.mixin({
+    beforeCreate,
     created,
     beforeDestroy
   })
 }
+
+function getFromStoreEntries(vm: VueClass) {
+  const fromStore = vm.$options[optionName]
+  if (!fromStore) {
+    return []
+  }
+
+  return Object.keys(fromStore).map(
+    key => ({ key, compute: fromStore[key] })
+  )
+}
diff --git a/test/index.ts b/test/index.ts
index c4ef8b0..367f35d 100644
--- a/test/index.ts
+++ b/test/index.ts
@@ -94,6 +94,64 @@ test(`can use this.data in ${optionName}`, done => {
   })
 })
 
+
+test(`fields in ${optionName} can be used in watch & computed`, done => {
+  Vue.use(Movue, { reaction })
+
+  const data = observable({
+    foo: 1
+  })
+
+  const onFooChange = jest.fn()
+  const onFoobarChange = jest.fn()
+
+  const vm = new Vue({
+    data() {
+      return {
+        bar: 2
+      }
+    },
+    computed: {
+      foobar() {
+        return this.foo + this.bar
+      }
+    },
+    [optionName]: {
+      foo() {
+        return data.foo
+      }
+    },
+    watch: {
+      foo(value) {
+        onFooChange(value)
+      },
+      foobar(value) {
+        onFoobarChange(value)
+      }
+    },
+    render (h) {
+      const vm: any = this
+      return h('div', `${vm.foobar}`)
+    }
+  }).$mount()
+
+  expect(vm.$el.textContent).toBe('3')
+
+  vm.bar++
+  runInAction(() => {
+    data.foo++
+  })
+
+  nextTick(() => {
+    expect(vm.$el.textContent).toBe('5')
+    expect(onFooChange.mock.calls).toHaveLength(1)
+    expect(onFooChange.mock.calls[0][0]).toBe(2)
+    expect(onFoobarChange.mock.calls).toHaveLength(1)
+    expect(onFoobarChange.mock.calls[0][0]).toBe(5)
+    done()
+  })
+})
+
 class Counter {
   @observable num = 0
   @computed get numPlus() {