diff --git a/packages/reactivity/src/collectionHandlers.ts b/packages/reactivity/src/collectionHandlers.ts
index 2b7785ae7eb..7c4b36fbe94 100644
--- a/packages/reactivity/src/collectionHandlers.ts
+++ b/packages/reactivity/src/collectionHandlers.ts
@@ -237,8 +237,10 @@ function createReadonlyMethod(type: TriggerOpTypes): Function {
   }
 }
 
+type Instrumentations = Record<string | symbol, Function | number>
+
 function createInstrumentations() {
-  const mutableInstrumentations: Record<string, Function | number> = {
+  const mutableInstrumentations: Instrumentations = {
     get(this: MapTypes, key: unknown) {
       return get(this, key)
     },
@@ -253,7 +255,7 @@ function createInstrumentations() {
     forEach: createForEach(false, false),
   }
 
-  const shallowInstrumentations: Record<string, Function | number> = {
+  const shallowInstrumentations: Instrumentations = {
     get(this: MapTypes, key: unknown) {
       return get(this, key, false, true)
     },
@@ -268,7 +270,7 @@ function createInstrumentations() {
     forEach: createForEach(false, true),
   }
 
-  const readonlyInstrumentations: Record<string, Function | number> = {
+  const readonlyInstrumentations: Instrumentations = {
     get(this: MapTypes, key: unknown) {
       return get(this, key, true)
     },
@@ -285,7 +287,7 @@ function createInstrumentations() {
     forEach: createForEach(true, false),
   }
 
-  const shallowReadonlyInstrumentations: Record<string, Function | number> = {
+  const shallowReadonlyInstrumentations: Instrumentations = {
     get(this: MapTypes, key: unknown) {
       return get(this, key, true, true)
     },
@@ -302,24 +304,18 @@ function createInstrumentations() {
     forEach: createForEach(true, true),
   }
 
-  const iteratorMethods = ['keys', 'values', 'entries', Symbol.iterator]
+  const iteratorMethods = [
+    'keys',
+    'values',
+    'entries',
+    Symbol.iterator,
+  ] as const
+
   iteratorMethods.forEach(method => {
-    mutableInstrumentations[method as string] = createIterableMethod(
-      method,
-      false,
-      false,
-    )
-    readonlyInstrumentations[method as string] = createIterableMethod(
-      method,
-      true,
-      false,
-    )
-    shallowInstrumentations[method as string] = createIterableMethod(
-      method,
-      false,
-      true,
-    )
-    shallowReadonlyInstrumentations[method as string] = createIterableMethod(
+    mutableInstrumentations[method] = createIterableMethod(method, false, false)
+    readonlyInstrumentations[method] = createIterableMethod(method, true, false)
+    shallowInstrumentations[method] = createIterableMethod(method, false, true)
+    shallowReadonlyInstrumentations[method] = createIterableMethod(
       method,
       true,
       true,