perf: improve memory usage

src/server-prefetch.ts

@@ -2,13 +2,10 @@ import {
   onServerPrefetch as onPrefetch,
   getCurrentInstance,
 } from '@vue/composition-api'
+import { ComponentInstance } from '@vue/composition-api/dist/component'
 
-const ssrRefFunctions = new Map<
-  ReturnType<typeof getCurrentInstance>,
-  (() => void)[]
->()
-
-const isPending = new Map<ReturnType<typeof getCurrentInstance>, number>()
+const ssrRefFunctions = new WeakMap<ComponentInstance, (() => void)[]>()
+const isPending = new WeakMap<ComponentInstance, number>()
 
 let noSetup: Array<() => any> = []
 
@@ -40,7 +37,7 @@ export function onServerPrefetch(cb: () => any) {
   })
 }
 
-export function onServerPrefetchEnd(cb: () => any) {
+export function onFinalServerPrefetch(cb: () => any) {
   if (!process.server) return
 
   const vm = getCurrentInstance()

src/ssr-ref.ts

@@ -1,5 +1,5 @@
 import { ref, Ref } from '@vue/composition-api'
-import { onServerPrefetchEnd } from './server-prefetch'
+import { onFinalServerPrefetch } from './server-prefetch'
 
 function getValue<T>(value: T | (() => T)): T {
   if (value instanceof Function) return value()
@@ -38,11 +38,10 @@ export const ssrRef = <T>(value: T | (() => T), key?: string): Ref<T> => {
   const initVal = clone(val)
   const _ref = ref(val) as Ref<T>
 
-  onServerPrefetchEnd(() => {
+  onFinalServerPrefetch(() => {
     if (value instanceof Function || initVal !== _ref.value)
       data[key] = _ref.value
   })
 
   return _ref
-
 }