Python requests.Session()的JavaScript替代方案

const axios = require('axios');

// 创建axios实例
const instance = axios.create({
  baseURL: 'https://api.example.com',
  timeout: 1000,
  headers: {'X-Custom-Header': 'foobar'}
});

// 请求拦截器
instance.interceptors.request.use(config => {
  // 在发送请求之前做些什么，例如添加token
  config.headers.Authorization = `Bearer ${localStorage.getItem('token')}`;
  return config;
}, error => {
  // 对请求错误做些什么
  return Promise.reject(error);
});

// 响应拦截器
instance.interceptors.response.use(response => {
  // 对响应数据做点什么
  return response;
}, error => {
  // 对响应错误做点什么
  return Promise.reject(error);
});

// 使用实例发送请求
instance.get('/data')
  .then(response => console.log(response.data))
  .catch(error => console.error(error));

// 创建一个存储cookies的函数
function setCookie(name, value, days) {
  var expires = "";
  if (days) {
    var date = new Date();
    date.setTime(date.getTime() + (days*24*60*60*1000));
    expires = "; expires=" + date.toUTCString();
  }
  document.cookie = name + "=" + (value || "")  + expires + "; path=/";
}

function getCookie(name) {
  var nameEQ = name + "=";
  var ca = document.cookie.split(';');
  for(var i=0;i < ca.length;i++) {
    var c = ca[i];
    while (c.charAt(0)==' ') c = c.substring(1,c.length);
    if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
  }
  return null;
}

// 发送请求
fetch('https://api.example.com/data', {
  method: 'GET',
  headers: {
    'Authorization': `Bearer ${getCookie('token')}`,
    'X-Custom-Header': 'foobar'
  }
})
.then(response => response.json())
.then(data => console.log(data))
.catch(error => console.error('Error:', error));