js bytes文件转图片显示和转pdf预览和上传

一、图片显示

img = data:application/pdf;base64,${res.bytes};

二、pdf预览

使用base64编码和Data URI Scheme：将字节数组进行base64编码，然后将生成的base64字符串和Data URI Scheme（以"data:application/pdf;base64,"为开头）组合成一个URL

const res = { bytes:'...' }
// 转换
const updatWordParam = async () => {
    fetch(`data:application/pdf;base64,${res.bytes}`).then(async (reBytes) => {
      const blob = await reBytes.blob();
      const newBlob = new Blob([blob], { type: 'application/pdf' });
      const file = new File([newBlob], '文件.pdf', { type: 'application/pdf' });
      const url = `${window.URL.createObjectURL(newBlob)}#toolbar=0`
      downUrlFile(url,'文件.pdf')
      uploadFile(file)
    });
}
// 下载
const downUrlFile = async (url, filename) => {
    const link = document.createElement('a');
    link.href = url;
    link.setAttribute('download', filename);
    link.click();
};
// 上传
const uploadFile = async (file) => {
     const formData = new FormData();
     formData.append('file', file);
     fetch('http://example.com/upload', {
        method: 'POST',
        body: formData
      })
        .then(response => {
            console.log('Success:', response);
        })
        .catch(error => {
            console.error('Error:', error);
        });
};