const data = { username: "example" };

​

fetch("https://example.com/profile", {

  method: "POST", // or 'PUT'

  headers: {

    "Content-Type": "application/json",

  },

  body: JSON.stringify(data),

})

  .then((response) => response.json())

  .then((data) => {

    console.log("Success:", data);

  })

  .catch((error) => {

    console.error("Error:", error);

  });