repro.mjs

import { ofetch } from "../dist/node.mjs";

let body;
body = { x: 1 }; // request body is "[object Object]"
// body = JSON.stringify(body); // request body is correctly received

const url ='https://d0348819-d0b4-4913-b739-360dfe6e0eef.mock.pstmn.io/debug';
const response = await ofetch(url, { body, method: "PATCH" });
console.log(response);