如何使用post请求下载文件详解编程语言

使用get请求下载文件非常简便，但是get请求的url有长度和大小的限制，所以当请求参数非常多时无法满足需求，所以改成post请求
const res = await fetch('xxxxxxxxx', { 
  method: 'post', 
  body: JSON.stringify(params), 
  credentials: 'include', 
  headers: { 
    'Cache-Control': 'max-age=0', 
    'Pragma': 'no-cache', 
    'Content-Type': 'application/json;charset=UTF-8', 
    'x-requested-with': 'fetch' 
  } 
  }); 
  const blob = await res.blob(); 
  if ('download' in document.createElement('a')) { 
  var a = document.createElement('a'); 
  a.style.display = 'none'; 
  var url = window.URL.createObjectURL(blob); 
  var filename = decodeURIComponent(res.headers.get('Content-Disposition')); 
  a.href = url; 
  a.download = filename; 
  document.body.appendChild(a); 
  a.click(); 
  window.URL.revokeObjectURL(url); 
  document.body.removeChild(a); 
  } else { 
  navigator.msSaveBlob(blob); 
}