关于typescript:js-四字节求和校验

校验文件最初四字节是否等于后面所有字节的累加值。

import { Modal } from "antd";const buf2hex = (buffer: Buffer) => {  return Array.prototype.map    .call(new Uint8Array(buffer), (x) => ("00" + x.toString(16)).slice(-2))    .join("");};/** 文件校验查看 */export const otaFileCheck = (originFileObj: Blob) => {  return new Promise((resolve, reject) => {    var reader = new FileReader();    reader.readAsArrayBuffer(originFileObj);    reader.onload = function () {      const result = this.result as Buffer;      const joindata = buf2hex(result);      const sumArr = [];      for (let i = 0; i < joindata.length / 2; i++) {        sumArr.push(joindata[i * 2] + joindata[i * 2 + 1]);      }      const fileHexCheck = `${sumArr[sumArr.length - 4]}${        sumArr[sumArr.length - 3]      }${sumArr[sumArr.length - 2]}${sumArr[sumArr.length - 1]}`;      let sum = 0;      for (let i = 0; i < sumArr.length - 4; i++) {        sum += parseInt("0x" + sumArr[i]);      }      const sumHexCheck = sum.toString(16).padStart(8, "0");      if (sumHexCheck !== fileHexCheck)        return Modal.error({          content: "文件校验未通过，请加密（四字节求和校验）！",        });      resolve(true);    };  });};