title: (react.js) dont lose position on screen when re-rendering
body: <p>I'm trying to implement an infinite scroll in react - but going up, not down. </p>
  
  <p>The component involved is rendering log files, but just one offset at a time. When you first land on the page, only the last offset is fetched and displayed, and as you scroll up, I'm fetching the previous offset from my DB, prepending the new text to the current text, and then re-rendering. </p>
  
  <p>The issue I'm running into is that when it re-renders, I lose the position of the current section of the log I'm viewing, and instead it jumps much higher up with the new log lines. </p>
  
  <p>The best solution I can think of is to keep track of where the user is when it is about to re-render, then calculate what the additional height is/will be from the new fetch, and then just using a window.scrollTop move to the correct position.</p>
  
  <p>I was hoping for something simpler, anyone have any thoughts?</p>