Function domdiff

index.js:438–532

(parentNode, // where changes happen
  currentNodes, // Array of current items/nodes
  futureNodes, // Array of future items/nodes
  options // optional object with one of the following properties
  //  before: domNode
  //  compare(generic, generic) => true if same generic
  //  node(generic) => Node
  )

  /*! (c) 2018 Andrea Giammarchi (ISC) */

  var domdiff = function domdiff(parentNode, // where changes happen
  currentNodes, // Array of current items/nodes
  futureNodes, // Array of future items/nodes
  options // optional object with one of the following properties
  //  before: domNode
  //  compare(generic, generic) => true if same generic
  //  node(generic) => Node
  ) {
    if (!options) options = {};
    var compare = options.compare || eqeq;
    var get = options.node || identity;
    var before = options.before == null ? null : get(options.before, 0);
    var currentLength = currentNodes.length;
    var currentEnd = currentLength;
    var currentStart = 0;
    var futureEnd = futureNodes.length;
    var futureStart = 0; // common prefix

    while (currentStart < currentEnd && futureStart < futureEnd && compare(currentNodes[currentStart], futureNodes[futureStart])) {
      currentStart++;
      futureStart++;
    } // common suffix


    while (currentStart < currentEnd && futureStart < futureEnd && compare(currentNodes[currentEnd - 1], futureNodes[futureEnd - 1])) {
      currentEnd--;
      futureEnd--;
    }

    var currentSame = currentStart === currentEnd;
    var futureSame = futureStart === futureEnd; // same list

    if (currentSame && futureSame) return futureNodes; // only stuff to add

    if (currentSame && futureStart < futureEnd) {
      append(get, parentNode, futureNodes, futureStart, futureEnd, next(get, currentNodes, currentStart, currentLength, before));
      return futureNodes;
    } // only stuff to remove


    if (futureSame && currentStart < currentEnd) {
      remove(get, currentNodes, currentStart, currentEnd);
      return futureNodes;
    }

    var currentChanges = currentEnd - currentStart;
    var futureChanges = futureEnd - futureStart;
    var i = -1; // 2 simple indels: the shortest sequence is a subsequence of the longest

    if (currentChanges < futureChanges) {
      i = indexOf$1(futureNodes, futureStart, futureEnd, currentNodes, currentStart, currentEnd, compare); // inner diff

      if (-1 < i) {
        append(get, parentNode, futureNodes, futureStart, i, get(currentNodes[currentStart], 0));
        append(get, parentNode, futureNodes, i + currentChanges, futureEnd, next(get, currentNodes, currentEnd, currentLength, before));
        return futureNodes;
      }
    }