fetch

fetch("로그인 API", {
  method: "post",
  body: JSON.stringify({
    id: "qawsedrf",
    password: "123456",
  }),
})
   .then((response) => {
    if (response.ok === true) {
      return response.json();
    }
    throw new Error("에러 발생!");
  })
  .catch((error) => console.log(error));
  .then((data) => {
    if (data.message === "login success") {
      localStorage.setItem("TOKEN", data.token);
      alert("로그인 성공");
    } else {
      alert("로그인 실패");
    }
  });

//data 예시

data : {
message: "login success",
token:"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJ1c2VyX2lkIjo1fQ.Dy3PPHIOFFe3ScGTb8x3hewItnpOcgC9YDdW7v27XHg"
 }