Javascript helpers to share urls programatically, on facebook or twitter

share.js

var S = module.exports = {}

/**
* If the page has og:meta tags facebook will parse the page and read them.
* So the options are optionals.
*/
S.onFacebook = function(options, callback){
  // New implementation
  // https://developers.facebook.com/docs/reference/dialogs/feed/
  if( callback ) {
    if ( !window.FB ) return
    var shareObj = {
      method: 'feed',
      link: window.location.href,
      caption: window.location.href
    }
    return FB.ui(_.extend(shareObj, options), callback)
  }

  // Old implementation, lets to choose where to post the item.
  // https://developers.facebook.com/docs/reference/plugins/share-links/
  var link = (options && options.link) || window.location.href
  var url = 'https://www.facebook.com/sharer/sharer.php?u='+
             encodeURIComponent(link)
  var w = 626, h = 436
  var l = (screen.width/2)-(w/2), t = (screen.height/2)-(h/2)
  window.open(url, 'facebook share', 'width='+w+',height='+h+',left='+l+',top='+t)
}

S.onTwitter = function(options){
  options = options || {}
  var shortenedUrl = encodeURIComponent(options.url)

  $.ajax({
    url: 'https://api-ssl.bitly.com/v3/shorten?access_token=a62d9787c155149efccd2613a77c220a51f32aee&longUrl=' + shortenedUrl,
    dataType: 'jsonp',
    type: 'GET'
  }).done(function(bitly){
      shortenedUrl = encodeURIComponent(bitly.data.url)
    })
    .always(function(bitly){
      var url = 'https://twitter.com/intent/tweet'
      url += '?url=' + shortenedUrl
      url += '&text=' + encodeURIComponent(options.text || I18n.t('javascripts.helpers.share.twitter_default_text'))
      url += '&hashtags=' + encodeURIComponent(I18n.t('javascripts.helpers.share.twitter_hashtag'))
      url += '&via=' + encodeURIComponent(I18n.t('javascripts.helpers.share.twitter_handler'))
      window.open(url, 'shareOnTwitter')
    })

  var w = 550, h = 420
  var l = (screen.width/2)-(w/2), t = (screen.height/2)-(h/2)
  window.open('', 'shareOnTwitter', 'width='+w+',height='+h+',left='+l+',top='+t)
}

S.getTwitterCount = function(url){
  var ajax = $.ajax({
    url: 'http://cdn.api.twitter.com/1/urls/count.json?url='+url,
    dataType : 'jsonp',
    type: 'GET'
  })
  return ajax.pipe(function(data){
    return data.count || 0
  })
}

S.getFacebookCount = function(url){
  var ajax = $.ajax({
    url: 'http://graph.facebook.com/'+url,
    type: 'GET'
  })
  return ajax.pipe(function(data){
    return data.shares || 0
  })
}

S.getCount = function(url){
  url = url || window.location.href
  var when = $.when(S.getTwitterCount(url), S.getFacebookCount(url))
  return when.pipe(function(){
    return _.reduce(arguments, function(sum, n) { return sum += n }) || 0
  })
}