hydra 是一个 node.js 的 C++ 模块，用来实现将复杂的计算任务委托给其他线程执行。
在 Js 代码中创建线程对象，执行 CPU 密集型函数，例如计算文件 HASH，加密解密等任务。在多核环境下，线程对象有助于更好的利用多核优势，以可控的方式减缓主线程压力。
This is a package for providing ability to create new threads in js. It helps you consciously assign cpu-bound tasks to a limited number of CPUs.
Windows, Linux and OS X
>=4.0.0
先全局安装 node-gyp
在工程根目录下运行 node-gyp configure
在工程根目录下运行 node-gyp rebuild
（编译过程大概需要 10s 左右，如果出现提示无权访问目录，请尝试 sudo node-gyp rebuild）
npm install -g node-gyp
node-gyp configure
node-gyp build (or **sudo node-gyp rebuild** )
将一个定时器抛给线程对象，等待2秒钟后，回到主线程执行回调函数。
var Thread = require('hydra')
var thread = new Thread()
thread.delayBySec(2, function(err) {
if(err) {
console.error(err)
}
console.log('after two secs')
thread.close()
console.log('thread running state: ' + thread.isRunning())
thread = null
})
console.log('thread running state: ' + thread.isRunning())Compute a file hash in other threads
var path = require('path')
var fs = require('fs')
var assert = require('assert')
var Thread = require('hydra')
var thread = new Thread()
console.log('before compute')
fs.readFile('./test.tmp', function(err, data) {
thread.sha2({data, type: 256}, function(err, data) {
if(err) {
return console.error(err)
}
console.log('result:')
console.log(data)
console.log('after compute')
console.log('The number of tasks queued：' + thread.numOfTasks())
})
console.log('The number of tasks queued：' + thread.numOfTasks())
})Promise
var path = require('path')
var fs = require('fs')
var assert = require('assert')
var Thread = require('hydra')
const Promise = require('bluebird')
const co = Promise.coroutine
var thread = new Thread()
fs.readFile('./test/thread.js', function(err, data) {
co(function*() {
var r = yield thread.sha2({data, type: 256})
console.log(r)
})()
})Ed25519 signature(EdDSA)
const Thread = require('hydra')
var thread = new Thread()
// async
thread.sign(new Buffer('a message'),
new Buffer('af9881fe34edfd3463cf3e14e22ad95a0608967e084d3ca1fc57be023040de59'),
function(err, data) {
console.log(data.toString('hex'))
})
// sync, compute in main thread
var data = Thread.sign(new Buffer('a message'),
new Buffer('af9881fe34edfd3463cf3e14e22ad95a0608967e084d3ca1fc57be023040de59'))close // 关闭线程
isRunning // 返回线程对象的线程是否运行(存在)
numOfTasks // 线程队列里CPU密集型任务个数
sha2 // SHA {256, 384, 512}
makeKeypair // 使用 Ed25519 生成密钥对
sign // Ed25519-DSA sign
verify // Ed25519 verify
BSD