fetch下载

import { userStatus } from '@xtc/user-status';

/**
 * 下载
 * @param url 地址
 * @param params 查询参数
 * @param fileName 文件名称，可不填
 */
export async function download(url: string, params?: object, fileName?: string) {
  if (params) {
    url += '?' + new URLSearchParams(<any>params).toString();
  }
  let headers = new Headers();
  const token = await userStatus.getToken();
  headers.append('Authorization', `Bearer ${token}`);
  fetch(url, {
    method: 'get',
    headers
  }).then((res => {
    let disposition = res.headers.get('content-disposition')
    let filename = disposition?.replace('attachment;filename=', '')
    return blobAndFileName(res.blob(), filename)
  }))
    .then((data: any) => {
      const link = document.createElement('a');
      var objectURL = URL.createObjectURL(data.blob);
      link.href = objectURL
      if (fileName) {
        link.download = fileName
      } else {
        link.download = decodeURIComponent(data.fileName)
      }
      link.click()
      URL.revokeObjectURL(objectURL)
    })
}

/**
 * 获取blob和文件名称
 * @param blob blob函数获取blob对象
 * @param fileName 文件名称
 * @returns Promise的blob和文件名称
 */
async function blobAndFileName(blob: Promise<any>, fileName: any) {
  let blobData = await blob
  return { blob: blobData, fileName }
}