如何清晰地分解两个几乎相似的函数

我有两个非常相似的函数内容,我想通过将代码变成一个函数来清晰地分解代码,但只有几行不同,更准确地说,其中一行比其他行多3行代码。

function doStuffForFacebook() { 
  var example = "toto"
  //about 7 lines of code

  resizeScale = 1
}

functiondoStuffforYoutube() {
  var example = "toto"
  //the VERY SAME 7 lines of code as those inside doStuffForFacebook()

  //the 3 lines which are different from above
  if ( typeof cryptoVideoX !== "undefined" && cryptoVideoX !== null && cryptoVideoX !== 0 ) {
     var vidRatio = cryptoVideoX / netVideoY;
  } else { //no crypto video add-on by source
      var vidRatio = netVideoRatio;
  }
  var manually_recalculated_width_to_have_full_screen_height_video = Math.round(vidRatio * winHeight);// fb only accepts rounded values
            $fbPlayer.attr('data-width', manually_recalculated_width_to_have_full_screen_height_video );

  resizeScale = 1
}

我真的很想把所有这些长的7+行分解为1个小的差异行,似乎可以改进。

是否有推荐的方法可以做到这一点,可以使用类似于回调的方法来实现类似的操作?

function doStuffForFacebook() { 
  resizeVideo(null);//nil because here no callback is necessary
}

functiondoStuffforYoutube() {
  resizeVideo(addSomeCodeCallback);
}
function resizeVideo(callback) {
  var example = "toto"
  //the 7 lines of common CODE
  callback();          
  resizeScale = 1
}
function addSomeCodeCallback() {
  if ( typeof cryptoVideoX !== "undefined" && cryptoVideoX !== null && cryptoVideoX !== 0 ) {
     var vidRatio = cryptoVideoX / netVideoY;
  } else { //no crypto video add-on by source
      var vidRatio = netVideoRatio;
  }
  var manually_recalculated_width_to_have_full_screen_height_video = Math.round(vidRatio * winHeight);// fb only accepts rounded values
            $fbPlayer.attr('data-width', 
  manually_recalculated_width_to_have_full_screen_height_video );
}

我知道我可以,但我宁愿不这样做:为之前的创建函数,为之后的创建另一个函数,因为它们更符合逻辑,而不是拆分,因为它们属于大型if/else块。

如何在尊重javascript最佳实践的前提下正确地做到这一点?