lib/walkers.js
function updateSimple(newList, oldList, rawNewValue ){

    var nlen = newList.length;
    var olen = oldList.length;
    var mlen = Math.min(nlen, olen);

    updateRange(0, mlen, newList, rawNewValue)
    if(nlen < olen){ //need add
      removeRange(nlen, olen-nlen, children);
    }else if(nlen > olen){
      addRange(olen, nlen, newList, rawNewValue);
    }
  }
function updateSimple(newList, oldList, rawNewValue ){

    var nlen = newList.length;
    var olen = oldList.length;
    var mlen = Math.min(nlen, olen);

    updateRange(0, mlen, newList, rawNewValue)
    if(nlen < olen){ //need add
      removeRange(nlen, olen-nlen, children);
    }else if(nlen > olen){
      addRange(olen, nlen, newList, rawNewValue);
    }
  }
function updateSimple ( newList , oldList , rawNewValue ) { var nlen = newList . length ; var olen = oldList . length ; var mlen = Math . min ( nlen , olen ) ; updateRange ( 0 , mlen , newList , rawNewValue ) if ( nlen < olen ) { //need add removeRange ( nlen , olen - nlen , children ) ; } else if ( nlen > olen ) { addRange ( olen , nlen , newList , rawNewValue ) ; } }
if the track is constant test.
if the track is constant test .