From e9024bf1b7456b9cf9b913c239502593364bc773 Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Sat, 22 Feb 2020 04:39:32 +0100
Subject: [PATCH] feat(reactivity): expose unref and shallowRef

---
 packages/reactivity/__tests__/ref.spec.ts   | 31 ++++++++++++++++++++-
 packages/reactivity/src/index.ts            |  2 +-
 packages/reactivity/src/ref.ts              | 20 +++++++++++--
 packages/runtime-core/src/componentProxy.ts |  9 +++---
 packages/runtime-core/src/index.ts          |  2 ++
 test-dts/ref.test-d.ts                      |  6 ++--
 6 files changed, 59 insertions(+), 11 deletions(-)

diff --git a/packages/reactivity/__tests__/ref.spec.ts b/packages/reactivity/__tests__/ref.spec.ts
index dc0cca6c..6620f7fd 100644
--- a/packages/reactivity/__tests__/ref.spec.ts
+++ b/packages/reactivity/__tests__/ref.spec.ts
@@ -1,5 +1,14 @@
-import { ref, effect, reactive, isRef, toRefs, Ref } from '../src/index'
+import {
+  ref,
+  effect,
+  reactive,
+  isRef,
+  toRefs,
+  Ref,
+  isReactive
+} from '../src/index'
 import { computed } from '@vue/runtime-dom'
+import { shallowRef, unref } from '../src/ref'
 
 describe('reactivity/ref', () => {
   it('should hold a value', () => {
@@ -129,6 +138,26 @@ describe('reactivity/ref', () => {
     expect(tupleRef.value[4].value).toBe(1)
   })
 
+  test('unref', () => {
+    expect(unref(1)).toBe(1)
+    expect(unref(ref(1))).toBe(1)
+  })
+
+  test('shallowRef', () => {
+    const sref = shallowRef({ a: 1 })
+    expect(isReactive(sref.value)).toBe(false)
+
+    let dummy
+    effect(() => {
+      dummy = sref.value.a
+    })
+    expect(dummy).toBe(1)
+
+    sref.value = { a: 2 }
+    expect(isReactive(sref.value)).toBe(false)
+    expect(dummy).toBe(2)
+  })
+
   test('isRef', () => {
     expect(isRef(ref(1))).toBe(true)
     expect(isRef(computed(() => 1))).toBe(true)
diff --git a/packages/reactivity/src/index.ts b/packages/reactivity/src/index.ts
index 040dd8c6..21a9eae8 100644
--- a/packages/reactivity/src/index.ts
+++ b/packages/reactivity/src/index.ts
@@ -1,4 +1,4 @@
-export { ref, isRef, toRefs, Ref, UnwrapRef } from './ref'
+export { ref, unref, shallowRef, isRef, toRefs, Ref, UnwrapRef } from './ref'
 export {
   reactive,
   isReactive,
diff --git a/packages/reactivity/src/ref.ts b/packages/reactivity/src/ref.ts
index 351dd1dd..f8863113 100644
--- a/packages/reactivity/src/ref.ts
+++ b/packages/reactivity/src/ref.ts
@@ -31,10 +31,22 @@ export function isRef(r: any): r is Ref {
 export function ref<T>(value: T): T extends Ref ? T : Ref<T>
 export function ref<T = any>(): Ref<T>
 export function ref(value?: unknown) {
+  return createRef(value)
+}
+
+export function shallowRef<T>(value: T): T extends Ref ? T : Ref<T>
+export function shallowRef<T = any>(): Ref<T>
+export function shallowRef(value?: unknown) {
+  return createRef(value, true)
+}
+
+function createRef(value: unknown, shallow = false) {
   if (isRef(value)) {
     return value
   }
-  value = convert(value)
+  if (!shallow) {
+    value = convert(value)
+  }
   const r = {
     _isRef: true,
     get value() {
@@ -42,7 +54,7 @@ export function ref(value?: unknown) {
       return value
     },
     set value(newVal) {
-      value = convert(newVal)
+      value = shallow ? newVal : convert(newVal)
       trigger(
         r,
         TriggerOpTypes.SET,
@@ -54,6 +66,10 @@ export function ref(value?: unknown) {
   return r
 }
 
+export function unref<T>(ref: T): T extends Ref<infer V> ? V : T {
+  return isRef(ref) ? (ref.value as any) : ref
+}
+
 export function toRefs<T extends object>(
   object: T
 ): { [K in keyof T]: Ref<T[K]> } {
diff --git a/packages/runtime-core/src/componentProxy.ts b/packages/runtime-core/src/componentProxy.ts
index 9e451110..a69d33da 100644
--- a/packages/runtime-core/src/componentProxy.ts
+++ b/packages/runtime-core/src/componentProxy.ts
@@ -13,7 +13,8 @@ import {
   isRef,
   isReactive,
   Ref,
-  ComputedRef
+  ComputedRef,
+  unref
 } from '@vue/reactivity'
 import { warn } from './warning'
 import { Slots } from './componentSlots'
@@ -84,8 +85,6 @@ const enum AccessTypes {
   OTHER
 }
 
-const unwrapRef = (val: unknown) => (isRef(val) ? val.value : val)
-
 export const PublicInstanceProxyHandlers: ProxyHandler<any> = {
   get(target: ComponentInternalInstance, key: string) {
     // fast path for unscopables when using `with` block
@@ -115,7 +114,7 @@ export const PublicInstanceProxyHandlers: ProxyHandler<any> = {
           case AccessTypes.DATA:
             return data[key]
           case AccessTypes.CONTEXT:
-            return unwrapRef(renderContext[key])
+            return unref(renderContext[key])
           case AccessTypes.PROPS:
             return propsProxy![key]
           // default: just fallthrough
@@ -125,7 +124,7 @@ export const PublicInstanceProxyHandlers: ProxyHandler<any> = {
         return data[key]
       } else if (hasOwn(renderContext, key)) {
         accessCache![key] = AccessTypes.CONTEXT
-        return unwrapRef(renderContext[key])
+        return unref(renderContext[key])
       } else if (type.props != null) {
         // only cache other properties when instance has declared (this stable)
         // props
diff --git a/packages/runtime-core/src/index.ts b/packages/runtime-core/src/index.ts
index b26c9a8f..8629d07f 100644
--- a/packages/runtime-core/src/index.ts
+++ b/packages/runtime-core/src/index.ts
@@ -3,6 +3,8 @@
 export const version = __VERSION__
 export {
   ref,
+  unref,
+  shallowRef,
   isRef,
   toRefs,
   reactive,
diff --git a/test-dts/ref.test-d.ts b/test-dts/ref.test-d.ts
index ad8c22fe..e1323fef 100644
--- a/test-dts/ref.test-d.ts
+++ b/test-dts/ref.test-d.ts
@@ -1,6 +1,5 @@
 import { expectType } from 'tsd'
-import { Ref, ref } from './index'
-import { isRef } from '@vue/reactivity'
+import { Ref, ref, isRef, unref } from './index'
 
 function foo(arg: number | Ref<number>) {
   // ref coercing
@@ -11,6 +10,9 @@ function foo(arg: number | Ref<number>) {
   if (isRef(arg)) {
     expectType<Ref<number>>(arg)
   }
+
+  // ref unwrapping
+  expectType<number>(unref(arg))
 }
 
 foo(1)