perf: use class for SetupContext

packages/runtime-vapor/src/component.ts

@@ -34,20 +34,39 @@ export type FunctionalComponent = SetupFn &
     displayName?: string
   }
 
-export type SetupContext<E = EmitsOptions> = E extends any
-  ? {
+export class SetupContext<E = EmitsOptions> {
   attrs: Data
   emit: EmitFn<E>
-      expose: (exposed?: Record<string, any>) => void
   slots: Readonly<StaticSlots>
+  expose: (exposed?: Record<string, any>) => void
+
+  constructor(instance: ComponentInternalInstance) {
+    this.attrs = instance.attrs
+    this.emit = instance.emit as EmitFn<E>
+    this.slots = instance.slots
+    this.expose = (exposed = {}) => {
+      instance.exposed = exposed
+    }
+  }
 }
-  : never
 
 export function createSetupContext(
   instance: ComponentInternalInstance,
 ): SetupContext {
-  const expose: SetupContext['expose'] = exposed => {
   if (__DEV__) {
+    // We use getters in dev in case libs like test-utils overwrite instance
+    // properties (overwrites should not be done in prod)
+    return Object.freeze({
+      get attrs() {
+        return getAttrsProxy(instance)
+      },
+      get slots() {
+        return getSlotsProxy(instance)
+      },
+      get emit() {
+        return (event: string, ...args: any[]) => instance.emit(event, ...args)
+      },
+      expose: (exposed?: Record<string, any>) => {
         if (instance.exposed) {
           warn(`expose() should be called only once per setup().`)
         }
@@ -66,32 +85,11 @@ export function createSetupContext(
             )
           }
         }
-    }
         instance.exposed = exposed || {}
-  }
-
-  if (__DEV__) {
-    // We use getters in dev in case libs like test-utils overwrite instance
-    // properties (overwrites should not be done in prod)
-    return Object.freeze({
-      get attrs() {
-        return getAttrsProxy(instance)
       },
-      get slots() {
-        return getSlotsProxy(instance)
-      },
-      get emit() {
-        return (event: string, ...args: any[]) => instance.emit(event, ...args)
-      },
-      expose,
-    })
+    }) as SetupContext
   } else {
-    return {
-      attrs: instance.attrs,
-      emit: instance.emit,
-      slots: instance.slots,
-      expose,
-    }
+    return new SetupContext(instance)
   }
 }