Question

hash.js

 var crypto = require('crypto'),
  fs = require('fs')

var algorithm = 'sha256',
   shasum = crypto.createHash(algorithm)

// Updating shasum with file content
var filename = __dirname + "/hufs.png",
  s = fs.ReadStream(filename)
s.on('data', function(data) {
  shasum.update(data)
})

// making digest
s.on('end', function() {
  var hash = shasum.digest('hex') // this var
  console.log(hash + '  ' + filename)
})

我有这个代码，然后我想从函数

中调用var'hash'

我不知道该怎么做，我想要修复代码

我需要你的帮助

Answer 1

要获取哈希的结果，必须在触发“结束”事件后获取值，并且如果您执行相同的代码

var hash;
s.on('end', function() {
  hash = shasum.digest('hex') // this var
  console.log(hash + '  ' + filename)
})
console.log(hash);

你的哈希将是“未定义的”，因为在事件触发后你的“console.log（hash）”将被执行

var crypto = require('crypto'),
  fs = require('fs')

var algorithm = 'sha256',
   shasum = crypto.createHash(algorithm)

// Updating shasum with file content
var filename = __dirname + "/3.png",
    s = fs.ReadStream(filename)

s.on('data', function(data) {
  shasum.update(data)
})

// making digest
var hash;
s.on('end', function() {
  hash = shasum.digest('hex') // this var
  console.log(hash + '  ' + filename)
})
// Here I simulate some code that will be executed after the "end" event was trigger
setTimeout(function(){
    console.log(hash);
},5000);

Node.js - 我想从函数中获取var'hash'

1 个答案: