ClientEntry not found issues when changing base path

[CodingFlow]

When changing base path from root, the client-entry file cannot be found, returns 404 error, when visiting the page in the browser in dev mode. In production build, client-entry is found, but stylesheet imported by client-entry is not found.

Steps to Reproduce

1. Create new Fresh project:

deno run -Ar jsr:@fresh/init

2. Change base path in main.ts and vite.config.ts:

main.ts

import { App, staticFiles } from "fresh";
import { define, type State } from "./utils.ts";

export const app = new App<State>({
  basePath: "/ui"
});

app.use(staticFiles());

// Pass a shared value from a middleware
app.use(async (ctx) => {
  ctx.state.shared = "hello";
  return await ctx.next();
});

// this is the same as the /api/:name route defined via a file. feel free to delete this!
app.get("/api2/:name", (ctx) => {
  const name = ctx.params.name;
  return new Response(
    `Hello, ${name.charAt(0).toUpperCase() + name.slice(1)}!`,
  );
});

// this can also be defined via a file. feel free to delete this!
const exampleLoggerMiddleware = define.middleware((ctx) => {
  console.log(`${ctx.req.method} ${ctx.req.url}`);
  return ctx.next();
});
app.use(exampleLoggerMiddleware);

// Include file-system based routes here
app.fsRoutes();

vite.config.ts

import { defineConfig } from "vite";
import { fresh } from "@fresh/plugin-vite";
import tailwindcss from "@tailwindcss/vite";

export default defineConfig({
  base: "/ui/",
  plugins: [fresh(), tailwindcss()],
});

3. a.

Run in dev:

deno task dev

4. a. See 404 errors for client-entry

3. b.

Run in prod:

deno task build
deno task start

4. b. See 404 error for stylesheet, but client-entry is found. It is looking for it at http://localhost:8000/assets/client-entry-ByNlewOz.css?__frsh_c=