feat(reactivity): add isShallow api

packages/reactivity/__tests__/ref.spec.ts

@@ -10,6 +10,7 @@ import {
 } from '../src/index'
 import { computed } from '@vue/runtime-dom'
 import { shallowRef, unref, customRef, triggerRef } from '../src/ref'
+import { isShallow } from '../src/reactive'
 
 describe('reactivity/ref', () => {
   it('should hold a value', () => {
@@ -227,6 +228,10 @@ describe('reactivity/ref', () => {
     expect(dummy).toBe(2)
   })
 
+  test('shallowRef isShallow', () => {
+    expect(isShallow(shallowRef({ a: 1 }))).toBe(true)
+  })
+
   test('isRef', () => {
     expect(isRef(ref(1))).toBe(true)
     expect(isRef(computed(() => 1))).toBe(true)

packages/reactivity/__tests__/shallowReactive.spec.ts

@@ -1,4 +1,10 @@
-import { isReactive, reactive, shallowReactive } from '../src/reactive'
+import {
+  isReactive,
+  isShallow,
+  reactive,
+  shallowReactive,
+  shallowReadonly
+} from '../src/reactive'
 
 import { effect } from '../src/effect'
 
@@ -24,6 +30,11 @@ describe('shallowReactive', () => {
     expect(isReactive(reactiveProxy.foo)).toBe(true)
   })
 
+  test('isShallow', () => {
+    expect(isShallow(shallowReactive({}))).toBe(true)
+    expect(isShallow(shallowReadonly({}))).toBe(true)
+  })
+
   describe('collections', () => {
     test('should be reactive', () => {
       const shallowSet = shallowReactive(new Set())

packages/reactivity/src/baseHandlers.ts

@@ -84,6 +84,8 @@ function createGetter(isReadonly = false, shallow = false) {
       return !isReadonly
     } else if (key === ReactiveFlags.IS_READONLY) {
       return isReadonly
+    } else if (key === ReactiveFlags.IS_SHALLOW) {
+      return shallow
     } else if (
       key === ReactiveFlags.RAW &&
       receiver ===

packages/reactivity/src/index.ts

@@ -22,6 +22,7 @@ export {
   readonly,
   isReactive,
   isReadonly,
+  isShallow,
   isProxy,
   shallowReactive,
   shallowReadonly,

packages/reactivity/src/reactive.ts

@@ -17,6 +17,7 @@ export const enum ReactiveFlags {
   SKIP = '__v_skip',
   IS_REACTIVE = '__v_isReactive',
   IS_READONLY = '__v_isReadonly',
+  IS_SHALLOW = '__v_isShallow',
   RAW = '__v_raw'
 }
 
@@ -24,6 +25,7 @@ export interface Target {
   [ReactiveFlags.SKIP]?: boolean
   [ReactiveFlags.IS_REACTIVE]?: boolean
   [ReactiveFlags.IS_READONLY]?: boolean
+  [ReactiveFlags.IS_SHALLOW]?: boolean
   [ReactiveFlags.RAW]?: any
 }
 
@@ -87,7 +89,7 @@ export type UnwrapNestedRefs<T> = T extends Ref ? T : UnwrapRefSimple<T>
 export function reactive<T extends object>(target: T): UnwrapNestedRefs<T>
 export function reactive(target: object) {
   // if trying to observe a readonly proxy, return the readonly version.
-  if (target && (target as Target)[ReactiveFlags.IS_READONLY]) {
+  if (isReadonly(target)) {
     return target
   }
   return createReactiveObject(
@@ -226,6 +228,10 @@ export function isReadonly(value: unknown): boolean {
   return !!(value && (value as Target)[ReactiveFlags.IS_READONLY])
 }
 
+export function isShallow(value: unknown): boolean {
+  return !!(value && (value as Target)[ReactiveFlags.IS_SHALLOW])
+}
+
 export function isProxy(value: unknown): boolean {
   return isReactive(value) || isReadonly(value)
 }

packages/reactivity/src/ref.ts

@@ -16,10 +16,6 @@ export interface Ref<T = any> {
    * autocomplete, so we use a private Symbol instead.
    */
   [RefSymbol]: true
-  /**
-   * @internal
-   */
-  _shallow?: boolean
 }
 
 type RefBase<T> = {
@@ -102,9 +98,9 @@ class RefImpl<T> {
   public dep?: Dep = undefined
   public readonly __v_isRef = true
 
-  constructor(value: T, public readonly _shallow: boolean) {
-    this._rawValue = _shallow ? value : toRaw(value)
-    this._value = _shallow ? value : toReactive(value)
+  constructor(value: T, public readonly __v_isShallow: boolean) {
+    this._rawValue = __v_isShallow ? value : toRaw(value)
+    this._value = __v_isShallow ? value : toReactive(value)
   }
 
   get value() {
@@ -113,10 +109,10 @@ class RefImpl<T> {
   }
 
   set value(newVal) {
-    newVal = this._shallow ? newVal : toRaw(newVal)
+    newVal = this.__v_isShallow ? newVal : toRaw(newVal)
     if (hasChanged(newVal, this._rawValue)) {
       this._rawValue = newVal
-      this._value = this._shallow ? newVal : toReactive(newVal)
+      this._value = this.__v_isShallow ? newVal : toReactive(newVal)
       triggerRefValue(this, newVal)
     }
   }

packages/runtime-core/src/apiWatch.ts

@@ -1,5 +1,6 @@
 import {
   isRef,
+  isShallow,
   Ref,
   ComputedRef,
   ReactiveEffect,
@@ -205,7 +206,7 @@ function doWatch(
 
   if (isRef(source)) {
     getter = () => source.value
-    forceTrigger = !!source._shallow
+    forceTrigger = isShallow(source)
   } else if (isReactive(source)) {
     getter = () => source
     deep = true

packages/runtime-core/src/customFormatter.ts

@@ -1,5 +1,6 @@
 import { isReactive, isReadonly, isRef, Ref, toRaw } from '@vue/reactivity'
 import { EMPTY_OBJ, extend, isArray, isFunction, isObject } from '@vue/shared'
+import { isShallow } from '../../reactivity/src/reactive'
 import { ComponentInternalInstance, ComponentOptions } from './component'
 import { ComponentPublicInstance } from './componentPublicInstance'
 
@@ -38,7 +39,7 @@ export function initCustomFormatter() {
         return [
           'div',
           {},
-          ['span', vueStyle, 'Reactive'],
+          ['span', vueStyle, isShallow(obj) ? 'ShallowReactive' : 'Reactive'],
           '<',
           formatValue(obj),
           `>${isReadonly(obj) ? ` (readonly)` : ``}`
@@ -47,7 +48,7 @@ export function initCustomFormatter() {
         return [
           'div',
           {},
-          ['span', vueStyle, 'Readonly'],
+          ['span', vueStyle, isShallow(obj) ? 'ShallowReadonly' : 'Readonly'],
           '<',
           formatValue(obj),
           '>'
@@ -181,7 +182,7 @@ export function initCustomFormatter() {
   }
 
   function genRefFlag(v: Ref) {
-    if (v._shallow) {
+    if (isShallow(v)) {
       return `ShallowRef`
     }
     if ((v as any).effect) {

packages/runtime-core/src/index.ts

@@ -15,6 +15,7 @@ export {
   isProxy,
   isReactive,
   isReadonly,
+  isShallow,
   // advanced
   customRef,
   triggerRef,