封装 jQuery.ajax

封装一个 jQuery.ajax

window.jQuery.ajax = function(url, method, body, success, fail){
  let request = new XMLHttpRequest()
  request.open(method, url) 
  request.onreadystatechange = ()=>{
    if(request.readyState === 4){
      if(request.status >= 200 && request.status < 300){
        success.call(undefined, request.responseText)
      }else if(request.status >= 400){
        fail.call(undefined, request)
      }
    }
  }
  request.send(body)
}

升级jQuery.ajax 满足 Promise 规则

window.jQuery.ajax = function({url, method, body}){
  return new Promise(function(resolve, reject){
    let request = new XMLHttpRequest()
    request.open(method, url) 
    request.onreadystatechange = ()=>{
      if(request.readyState === 4){
        if(request.status >= 200 && request.status < 300){
          resolve.call(undefined, request.responseText)
        }else if(request.status >= 400){
          reject.call(undefined, request)
        }
      }
    }
    request.send(body)
  })
}