fix(assets): set js content-type on dev bundled asset handler (#748)

Author: harlan-zw

packages/script/src/assets.ts

@@ -1,6 +1,6 @@
 importtype{NitroConfig}from'nitropack'
 import{addDevServerHandler,extendRouteRules,tryUseNuxt,useNuxt}from'@nuxt/kit'
-import{createError,eventHandler,lazyEventHandler}from'h3'
+import{createError,eventHandler,lazyEventHandler,setHeader}from'h3'
 import{fetch}from'ofetch'
 import{join,resolve}from'pathe'
 import{joinURL}from'ufo'
@@ -58,6 +58,8 @@ export function setupPublicAssetStrategy(assetsBaseURL: string) {
 if(!scriptDescriptor||scriptDescriptorinstanceofError)
 throwcreateError({statusCode: 404})
 
+setHeader(event,'content-type','application/javascript; charset=utf-8')
+
 // Use pre-rendered content which includes proxy rewrites for first-party mode
 if(scriptDescriptor.content){
 returnscriptDescriptor.content