计算文件hash值(SHA1)

参考自https://www.jianshu.com/p/59a06a08efac
参考自
获取到文件对象后

//导入
import CryptoJS from "crypto-js";
//上传文件触发事件
uploadCrt(param) {
      let contractFile = param.file;
      let reader = new FileReader(),
        self = this;
      let blobSlice =
        File.prototype.mozSlice ||
        File.prototype.webkitSlice ||
        File.prototype.slice;
      let chunkSize = 10 * 1024 * 1024;
      let chunks = Math.ceil(contractFile.size / chunkSize);
      let currentChunk = 0;
      let hasher = CryptoJS.algo.SHA1.create();
      console.log(`CryptoJS.algo.SHA1.create`, CryptoJS.algo.SHA1.create);
      let start = currentChunk * chunkSize;
      let end =
        start + chunkSize >= contractFile.size
          ? contractFile.size
          : start + chunkSize;
      reader.readAsArrayBuffer(blobSlice.call(contractFile, start, end));
      reader.onload = function(evt) {
        let fileStr = evt.target.result;
        let tmpWordArray = self.arrayBufferToWordArray(fileStr);
        hasher.update(tmpWordArray);
        currentChunk += 1;
        fileStr = null;
        tmpWordArray = null;
        if (currentChunk < chunks) {
          let start = currentChunk * chunkSize;
          let end =
            start + chunkSize >= contractFile.size
              ? contractFile.size
              : start + chunkSize;
          reader.readAsArrayBuffer(blobSlice.call(contractFile, start, end));
        }
      };
      reader.onloadend = function() {
        contractFile = null;
        let hash = hasher.finalize();
        hash.toString(); //计算结果
        console.log(
          `hash.toString().length`,
          hash.toString() === "d6de0ccc33b360d5e04125b8d9e0f38962d10d08"
        );
        // 可以百度或命令行‘在线计算hash文件工具，然后将计算后的值与hash.tostring()的 值进行对比 SHA1生成的是40位的字符串’
        hasher = null;
        blobSlice = null;
        reader = null;
        hash = null;
      };
    },
    arrayBufferToWordArray(ab) {
      let i8a = new Uint8Array(ab);
      let a = [];
      for (let i = 0; i < i8a.length; i += 4) {
        a.push(
          (i8a[i] << 24) | (i8a[i + 1] << 16) | (i8a[i + 2] << 8) | i8a[i + 3]
        );
      }
      return CryptoJS.lib.WordArray.create(a, i8a.length);
    },

//导入
import CryptoJS from "crypto-js";

getHash(file){
let reader = new FileReader();
        // 读取文件 file
        reader.readAsArrayBuffer(file);
 
        reader.onload = function () {
            var wordArray = CryptoJS.lib.WordArray.create(reader.result);
            var hash = CryptoJS.SHA1(wordArray).toString(); // 计算其他加密算法，SHA1改为MD5、SHA256即可
            console.log('hash:', hash)
        };
}

本文非原创，在作者的基础上根据自己需求做了修改

以上。