Function patch

index.js:124–317

(parent, node, oldVNode, newVNode, listener, isSvg)

}

var patch = (parent, node, oldVNode, newVNode, listener, isSvg) => {
  if (oldVNode === newVNode) {
  } else if (
    oldVNode != null &&
    oldVNode.type === TEXT_NODE &&
    newVNode.type === TEXT_NODE
  ) {
    if (oldVNode.tag !== newVNode.tag) node.nodeValue = newVNode.tag
  } else if (oldVNode == null || oldVNode.tag !== newVNode.tag) {
    node = parent.insertBefore(
      createNode((newVNode = maybeVNode(newVNode)), listener, isSvg),
      node
    )
    if (oldVNode != null) {
      parent.removeChild(oldVNode.node)
    }
  } else {
    var tmpVKid
    var oldVKid

    var oldKey
    var newKey

    var oldProps = oldVNode.props
    var newProps = newVNode.props

    var oldVKids = oldVNode.children
    var newVKids = newVNode.children

    var oldHead = 0
    var newHead = 0
    var oldTail = oldVKids.length - 1
    var newTail = newVKids.length - 1

    isSvg = isSvg || newVNode.tag === "svg"

    for (var i in { ...oldProps, ...newProps }) {
      if (
        (i === "value" || i === "selected" || i === "checked"
          ? node[i]
          : oldProps[i]) !== newProps[i]
      ) {
        patchProperty(node, i, oldProps[i], newProps[i], listener, isSvg)
      }
    }

    while (newHead <= newTail && oldHead <= oldTail) {
      if (
        (oldKey = getKey(oldVKids[oldHead])) == null ||
        oldKey !== getKey(newVKids[newHead])
      ) {
        break
      }

      patch(
        node,
        oldVKids[oldHead].node,
        oldVKids[oldHead],