download emoticons

py.js

var https = require('https')
var http = require('http')
var fs = require('fs')
var path = require('path')
var url = 'https://raw.githubusercontent.com/spacelan/wechat-emoticon/master/emoticons.json'

https.get(url, function(res) {
  var data = ''
  res.setEncoding('utf8')
  res.on('data', function(chunk) {
    data += chunk
  })
  res.on('end', function() {
    download(JSON.parse(data))
  })
})

function loopAsync(turns, work, callback) {
  var currentTurn = 0
  var isDone = false
  var hasNext = false

  function done() {
    isDone = true
    callback.apply(this, arguments)
  }

  function next() {
    if (isDone) return
    hasNext = true

    while (!isDone && currentTurn < turns && hasNext) {
      hasNext = false
      work.call(this, currentTurn++, next, done)
    }

    if (currentTurn >= turns && hasNext) {
      isDone = true
      callback()
    }
  }

  next()
}

function download(emoticons) {
  loopAsync(emoticons.length, function (index, next, done) {
    var emoticon = emoticons[index]
    
    http.get(emoticon.url, function(res) {
      var name = path.join(__dirname, emoticon.md5 + '.gif')
      res.pipe(fs.createWriteStream(name))
      res.on('end', next)
    })
  }, function() {
    console.log('下载图片完成')
  })
}