diff --git a/packages/plugin-vue/src/handleHotUpdate.ts b/packages/plugin-vue/src/handleHotUpdate.ts
index e47d3b17..ae07de16 100644
--- a/packages/plugin-vue/src/handleHotUpdate.ts
+++ b/packages/plugin-vue/src/handleHotUpdate.ts
@@ -144,7 +144,7 @@ export async function handleHotUpdate({
   return [...affectedModules].filter(Boolean) as ModuleNode[]
 }
 
-export function isEqualBlock(a: SFCBlock | null, b: SFCBlock | null) {
+export function isEqualBlock(a: SFCBlock | null, b: SFCBlock | null): boolean {
   if (!a && !b) return true
   if (!a || !b) return false
   // src imports will trigger their own updates
@@ -161,7 +161,7 @@ export function isEqualBlock(a: SFCBlock | null, b: SFCBlock | null) {
 export function isOnlyTemplateChanged(
   prev: SFCDescriptor,
   next: SFCDescriptor
-) {
+): boolean {
   return (
     isEqualBlock(prev.script, next.script) &&
     isEqualBlock(prev.scriptSetup, next.scriptSetup) &&
diff --git a/packages/plugin-vue/src/script.ts b/packages/plugin-vue/src/script.ts
index a80341c7..4857ad8c 100644
--- a/packages/plugin-vue/src/script.ts
+++ b/packages/plugin-vue/src/script.ts
@@ -17,7 +17,7 @@ export function setResolvedScript(
   descriptor: SFCDescriptor,
   script: SFCScriptBlock,
   ssr: boolean
-) {
+): void {
   ;(ssr ? ssrCache : clientCache).set(descriptor, script)
 }
 
@@ -25,7 +25,7 @@ export function resolveScript(
   descriptor: SFCDescriptor,
   options: ResolvedOptions,
   ssr: boolean
-) {
+): SFCScriptBlock | null {
   if (!descriptor.script && !descriptor.scriptSetup) {
     return null
   }
diff --git a/packages/plugin-vue/src/utils/descriptorCache.ts b/packages/plugin-vue/src/utils/descriptorCache.ts
index dc1cc7fc..d03643dc 100644
--- a/packages/plugin-vue/src/utils/descriptorCache.ts
+++ b/packages/plugin-vue/src/utils/descriptorCache.ts
@@ -1,7 +1,13 @@
 import path from 'path'
 import slash from 'slash'
 import hash from 'hash-sum'
-import { parse, SFCDescriptor } from '@vue/compiler-sfc'
+import { CompilerError, parse, SFCDescriptor } from '@vue/compiler-sfc'
+
+// node_modules/@vue/compiler-sfc/dist/compiler-sfc.d.ts SFCParseResult should be exported so it can be re-used
+export interface SFCParseResult {
+  descriptor: SFCDescriptor
+  errors: Array<CompilerError | SyntaxError>
+}
 
 const cache = new Map<string, SFCDescriptor>()
 const prevCache = new Map<string, SFCDescriptor | undefined>()
@@ -11,7 +17,7 @@ export function createDescriptor(
   source: string,
   root: string,
   isProduction: boolean | undefined
-) {
+): SFCParseResult {
   const { descriptor, errors } = parse(source, {
     filename,
     sourceMap: true
@@ -26,15 +32,21 @@ export function createDescriptor(
   return { descriptor, errors }
 }
 
-export function getPrevDescriptor(filename: string) {
+export function getPrevDescriptor(filename: string): SFCDescriptor | undefined {
   return prevCache.get(filename)
 }
 
-export function setPrevDescriptor(filename: string, entry: SFCDescriptor) {
+export function setPrevDescriptor(
+  filename: string,
+  entry: SFCDescriptor
+): void {
   prevCache.set(filename, entry)
 }
 
-export function getDescriptor(filename: string, errorOnMissing = true) {
+export function getDescriptor(
+  filename: string,
+  errorOnMissing = true
+): SFCDescriptor | undefined {
   if (cache.has(filename)) {
     return cache.get(filename)!
   }
@@ -46,6 +58,6 @@ export function getDescriptor(filename: string, errorOnMissing = true) {
   }
 }
 
-export function setDescriptor(filename: string, entry: SFCDescriptor) {
+export function setDescriptor(filename: string, entry: SFCDescriptor): void {
   cache.set(filename, entry)
 }
diff --git a/packages/plugin-vue/src/utils/query.ts b/packages/plugin-vue/src/utils/query.ts
index c0bafedc..bd1c6394 100644
--- a/packages/plugin-vue/src/utils/query.ts
+++ b/packages/plugin-vue/src/utils/query.ts
@@ -9,7 +9,9 @@ export interface VueQuery {
   raw?: boolean
 }
 
-export function parseVueRequest(id: string) {
+export function parseVueRequest(
+  id: string
+): { filename: string; query: VueQuery } {
   const [filename, rawQuery] = id.split(`?`, 2)
   const query = qs.parse(rawQuery) as VueQuery
   if (query.vue != null) {