fix(rsc): use proper base+origin for source map lookup

Author: hybrist

packages/plugin-rsc/src/react/browser.ts

@@ -54,8 +54,10 @@ export function findSourceMapURL(
   filename: string,
   environmentName: string,
 ): string | null {
-  // TODO: respect config.server.origin and config.base?
-  const url = new URL('/__vite_rsc_findSourceMapURL', window.location.origin)
+  // Respect config.base by using import.meta.env.BASE_URL
+  const base = import.meta.env.BASE_URL.replace(/\/$/, '')
+  // Respect asset origin (e.g. server.origin) by using import.meta.url
+  const url = new URL(base + '/__vite_rsc_findSourceMapURL', import.meta.url)
   url.searchParams.set('filename', filename)
   url.searchParams.set('environmentName', environmentName)
   return url.toString()