function updateDOMProps()

in assets/js/vue.js [7594:7662]
50 lines of code
26 McCabe index (conditional complexity)

  function updateDOMProps (oldVnode, vnode) {
    if (isUndef(oldVnode.data.domProps) && isUndef(vnode.data.domProps)) {
      return
    }
    var key, cur;
    var elm = vnode.elm;
    var oldProps = oldVnode.data.domProps || {};
    var props = vnode.data.domProps || {};
    // clone observed objects, as the user probably wants to mutate it
    if (isDef(props.__ob__)) {
      props = vnode.data.domProps = extend({}, props);
    }

    for (key in oldProps) {
      if (!(key in props)) {
        elm[key] = '';
      }
    }

    for (key in props) {
      cur = props[key];
      // ignore children if the node has textContent or innerHTML,
      // as these will throw away existing DOM nodes and cause removal errors
      // on subsequent patches (#3360)
      if (key === 'textContent' || key === 'innerHTML') {
        if (vnode.children) { vnode.children.length = 0; }
        if (cur === oldProps[key]) { continue }
        // #6601 work around Chrome version <= 55 bug where single textNode
        // replaced by innerHTML/textContent retains its parentNode property
        if (elm.childNodes.length === 1) {
          elm.removeChild(elm.childNodes[0]);
        }
      }

      if (key === 'value' && elm.tagName !== 'PROGRESS') {
        // store value as _value as well since
        // non-string values will be stringified
        elm._value = cur;
        // avoid resetting cursor position when value is the same
        var strCur = isUndef(cur) ? '' : String(cur);
        if (shouldUpdateValue(elm, strCur)) {
          elm.value = strCur;
        }
      } else if (key === 'innerHTML' && isSVG(elm.tagName) && isUndef(elm.innerHTML)) {
        // IE doesn't support innerHTML for SVG elements
        svgContainer = svgContainer || document.createElement('div');
        svgContainer.innerHTML = "<svg>" + cur + "</svg>";
        var svg = svgContainer.firstChild;
        while (elm.firstChild) {
          elm.removeChild(elm.firstChild);
        }
        while (svg.firstChild) {
          elm.appendChild(svg.firstChild);
        }
      } else if (
        // skip the update if old and new VDOM state is the same.
        // `value` is handled separately because the DOM value may be temporarily
        // out of sync with VDOM state due to focus, composition and modifiers.
        // This  #4521 by skipping the unnecesarry `checked` update.
        cur !== oldProps[key]
      ) {
        // some property updates can throw
        // e.g. `value` on <progress> w/ non-finite value
        try {
          elm[key] = cur;
        } catch (e) {}
      }
    }
  }