SyntaxError: Unexpected end of JSON input on return bodyCache[key] = raw[key]();

[fzn0x]

What version of Hono are you using?

^4.2.6

What runtime/platform is your app running on?

Bun 1.1.3

What steps can reproduce the bug?

You can try modify request like this to get this error.

import { z } from "zod";

const escapeHtml = (text: string) => {
  const map: Record<string, string> = {
    "<": "&lt;",
    ">": "&gt;",
    "&": "&amp;",
    "'": "&#39;",
    '"': "&quot;",
    "/": "&#47;",
  };
  return text.replace(/[<>&'"\/]/g, (char: string): string => map[char]);
};

const safeHtmlString = z.string().transform((str) => escapeHtml(str));

export default safeHtmlString;

app.use(async (c, next) => {
  const json = await c.req.json();
  for (let key in json) {
    if (json.hasOwnProperty(key)) {
      if (typeof json[key] === "string") {
        json[key] = sanitize.parse(json[key]);
      }
    }
  }

  // Modify request like hono/validator
  c.req.bodyCache.json = json;

  await next();
});

What is the expected behavior?

json request modified and no error while running server with Bun.

What do you see instead?

79 | return await new Response(body)key;
80 | })();
81 | }
82 | }
83 |
84 | return bodyCache[key] = rawkey;
^
SyntaxError: Unexpected end of JSON input

Additional information

No response

[fzn0x]

I suspect it related with request.clone() issue from Bun because it also returns SyntaxError: Unexpected end of JSON input,

oven-sh/bun#6468

[yusukebe]

Hi @fzn0x

Maybe the body is blank or not a valid JSON string. So, you have to handle the error yourself.

[fzn0x]

It's happen after I call const json = await c.req.json();

@yusukebe

[fzn0x]

Solved thanks!! I think we could improve the message in the future :)

app.use(async (c, next) => {
  try {
    const json = await c.req.json();

    for (let key in json) {
      if (json.hasOwnProperty(key)) {
        if (typeof json[key] === "string") {
          json[key] = sanitize.parse(json[key]);
        }
      }
    }

    c.req.bodyCache.json = json;
  } catch (_err) {
  } finally {
    await next();
  }
});