diff --git a/packages/reactivity/src/reactive.ts b/packages/reactivity/src/reactive.ts
index eec2eab1a..7b168a3b8 100644
--- a/packages/reactivity/src/reactive.ts
+++ b/packages/reactivity/src/reactive.ts
@@ -1,4 +1,4 @@
-import { isObject, toTypeString } from '@vue/shared'
+import { isObject, toRawType } from '@vue/shared'
 import { mutableHandlers, readonlyHandlers } from './baseHandlers'
 import {
   mutableCollectionHandlers,
@@ -29,16 +29,14 @@ const nonReactiveValues = new WeakSet<any>()
 
 const collectionTypes = new Set<Function>([Set, Map, WeakMap, WeakSet])
 const isObservableType = /*#__PURE__*/ makeMap(
-  ['Object', 'Array', 'Map', 'Set', 'WeakMap', 'WeakSet']
-    .map(t => `[object ${t}]`)
-    .join(',')
+  'Object,Array,Map,Set,WeakMap,WeakSet'
 )
 
 const canObserve = (value: any): boolean => {
   return (
     !value._isVue &&
     !value._isVNode &&
-    isObservableType(toTypeString(value)) &&
+    isObservableType(toRawType(value)) &&
     !nonReactiveValues.has(value)
   )
 }
diff --git a/packages/runtime-core/src/componentProps.ts b/packages/runtime-core/src/componentProps.ts
index 8f9e603e2..146e0ff3c 100644
--- a/packages/runtime-core/src/componentProps.ts
+++ b/packages/runtime-core/src/componentProps.ts
@@ -10,7 +10,7 @@ import {
   isObject,
   isReservedProp,
   hasOwn,
-  toTypeString,
+  toRawType,
   PatchFlags,
   makeMap
 } from '@vue/shared'
@@ -390,10 +390,6 @@ function styleValue(value: unknown, type: string): string {
   }
 }
 
-function toRawType(value: unknown): string {
-  return toTypeString(value).slice(8, -1)
-}
-
 function isExplicable(type: string): boolean {
   const explicitTypes = ['string', 'number', 'boolean']
   return explicitTypes.some(elem => type.toLowerCase() === elem)
diff --git a/packages/shared/src/index.ts b/packages/shared/src/index.ts
index 5c7cc6a2e..38b1e2920 100644
--- a/packages/shared/src/index.ts
+++ b/packages/shared/src/index.ts
@@ -48,6 +48,10 @@ export const objectToString = Object.prototype.toString
 export const toTypeString = (value: unknown): string =>
   objectToString.call(value)
 
+export function toRawType(value: unknown): string {
+  return toTypeString(value).slice(8, -1)
+}
+
 export const isPlainObject = (val: unknown): val is object =>
   toTypeString(val) === '[object Object]'