html-pdf

1.转Buffer数据
     const PDFBuffer = new Promise((resolve, reject) => {
            htmlToPdf.create(html, {format:'A3'}).toBuffer(
                (err, buffer) => {
                    err ? reject(err) : resolve(buffer);
                });
        });
        const buffer = await PDFBuffer;

2.转化为服务端文件
       htmlToPdf.create(html, {format:'A4'}).toFile('./businesscard.pdf', 
            function(err, res) {
          if (err) return console.log(err);
          fileStream = fs.createReadStream(res.filename);
        });

3.toStream? 具体使用不明了

  htmlToPdf().from(htmlStream).toStream((err, stream) => {  

       if (err) {  

            console.error(err);  

        } else {  

           stream.pipe(pdfStream);  

       }  

       });