[Vuejs]-How to scroll to latest message when have new message with Vuejs

Try to cover your code with nextTick(() => {})
like this:

  this.$nextTick(() => {
     document.getElementsByClassName('msg_history')[0].scrollTop = some value;                      
  })    

This will wait till all rendering has done.
And checkout the way of calc the top location below:

How to keep a scrollbar always bottom?