actualize/lib/setAttrs.js

DOM patching algorithm

/**
 * @param {*|Element} nodeA
 * @param {*|Element} nodeB
 */
function setAttrs(nodeA, nodeB) {
  const names = new Set
  let attr, value
  for(attr of nodeA.attributes) {
    names.add(attr.name)
    value = nodeB.getAttribute(attr.name)
    if(value === null) {
      nodeA.removeAttribute(attr.name)
      continue
    }
    if(attr.value !== value) {
      attr.value = value
    }
  }
  for(attr of nodeB.attributes) {
    if(!names.has(attr.name)) {
      nodeA.setAttribute(attr.name, attr.value)
    }
  }
  switch(nodeA.tagName) {
    case 'OPTION':
      nodeA.selected = nodeB.selected
      break
    case 'INPUT':
      nodeA.checked = nodeB.checked
      nodeA.indeterminate = nodeB.indeterminate
    case 'TEXTAREA':
      nodeA.value = nodeB.value
  }
}

module.exports = setAttrs