javascript - 添加 cipher.update() 和 cipher.final() 并连接它们有什么区别？

Question

和有什么区别

   let cipher = crypto.createCipheriv('aes-128-cbc', key, iv);
   const res = Buffer.concat([encrypter.update(data), encrypter.final()]);

和

let cipher = crypto.createCipheriv('aes-128-cbc', key, iv);
const res = cipher.update(data)+ cipher .final();