Japanese text misrenders in JSON without charset on Safari/WebKit

[s7tya]

What version of Hono are you using?

4.6.19

What runtime/platform is your app running on? (with version if possible)

deno 2.1.7

What steps can reproduce the bug?

Because the charset parameter was removed in #3743, the Japanese text in the JSON response no longer displays correctly in Safari.

import { Hono } from "jsr:@hono/[email protected]";

const app = new Hono();

app.get("/", (c) => {
  return c.json({ "message": "日本語テキスト" });
});

Deno.serve(app.fetch);

If you revert the version from 4.6.19 to 4.6.13, which isn’t affected by that change, the text displays correctly.

What is the expected behavior?

What do you see instead?

Additional information

This issue is caused by the known WebKit bug described here:
https://bugs.webkit.org/show_bug.cgi?id=197369
It has existed since 2019 and still hasn’t been fixed.

[EdamAme-x]

Thanks for the report.
This is a webkit's bug and there is nothing we can do about it! (for web standards)

But, we do have a solution (or workaround).

import { Hono } from 'hono'

const app = new Hono()

app.use(async (c, next) => {
  await next();
  if (c.finalized && c.res.headers.get("Content-Type") === "application/json") {
    c.res.headers.set("Content-Type", "application/json; charset=utf-8")
  }
})
  
app.get('/hello', (c) => {
  const name = c.req.query('name')
  return c.json(`${name} いず くーる！`)
})

export default app

[s7tya]

That workaround worked successfully. Thank you very much. I understand that this bug is in WebKit, but I believe it could be problematic if simply updating the patch version of hono ends up breaking the display for many users.

[yusukebe]

Hi @s7tya

Thank you for the issue. I didn't realize that problem. But as you said, this is not a Hono-side bug.

but I believe it could be problematic if simply updating the patch version of hono ends up breaking the display for many users.

Indeed. But now, I can't decide whether we should revert #3743 or not. For now, I label this as not a bug.