如何取消请求的发送

const controller = new AbortController();
const signal = controller.signal;
fetch('https://somewhere', { signal })
controller.abort()

var CancelToken = axios.CancelToken;
var source = CancelToken.source();

axios.get('/https://somewhere', {
  cancelToken: source.token
}

source.cancel()

const xhr = new XMLHttpRequest(),
  method = "GET",
  url = "https://developer.mozilla.org/";
xhr.open(method, url, true);
 
xhr.send();
 
// 取消发送请求
xhr.abort();

const controller = new AbortController()
const signal = controller.signal
 
const downloadBtn = document.querySelector('.download');
const abortBtn = document.querySelector('.abort');
 
downloadBtn.addEventListener('click', fetchVideo);
 
// 点击取消按钮时，取消请求的发送
abortBtn.addEventListener('click', function() {
  controller.abort();
  console.log('Download aborted');
});
 
function fetchVideo() {
  ...
  fetch(url, {signal}).then(function(response) {
    ...
  }).catch(function(e) {
   // 请求被取消之后将会得到一个 AbortError
    reports.textContent = 'Download error: ' + e.message;
  })
}

const CancelToken = axios.CancelToken;
const source = CancelToken.source();
 
axios
  .get("/user/12345", {
    cancelToken: source.token,
  })
  .catch(function (thrown) {
    if (axios.isCancel(thrown)) {
      console.log("Request canceled", thrown.message);
    } else {
      // handle error
    }
  });
 
axios.post(
  "/user/12345",
  {
    name: "new name",
  },
  {
    cancelToken: source.token,
  },
);
 
// cancel the request (the message parameter is optional)
source.cancel("Operation canceled by the user.");