Function diffVnode

packages/qwik/src/core/render/dom/visitor.ts:371–509

(
  rCtx: RenderContext,
  oldVnode: ProcessedJSXNode,
  newVnode: ProcessedJSXNode,
  flags: number
)

};

export const diffVnode = (
  rCtx: RenderContext,
  oldVnode: ProcessedJSXNode,
  newVnode: ProcessedJSXNode,
  flags: number
): ValueOrPromise<void> => {
  assertEqual(oldVnode.$type$, newVnode.$type$, 'old and new vnodes type must be the same');
  assertEqual(oldVnode.$key$, newVnode.$key$, 'old and new vnodes key must be the same');
  assertEqual(oldVnode.$id$, newVnode.$id$, 'old and new vnodes key must be the same');
  const elm = oldVnode.$elm$;
  const tag = newVnode.$type$;
  const staticCtx = rCtx.$static$;
  const containerState = staticCtx.$containerState$;
  const currentComponent = rCtx.$cmpCtx$;
  assertDefined(elm, 'while patching element must be defined');
  assertDefined(currentComponent, 'while patching current component must be defined');

  newVnode.$elm$ = elm;

  // Render text nodes
  if (tag === '#text') {
    staticCtx.$visited$.push(elm);
    const signal = newVnode.$signal$;
    if (signal) {
      newVnode.$text$ = jsxToString(
        trackSignal(signal, [4, currentComponent.$element$, signal, elm as Text])
      );
    }
    setProperty(staticCtx, elm, 'data', newVnode.$text$);
    return;
  } else if (tag === '#signal') {
    return;
  }
  assertQwikElement(elm);

  const props = newVnode.$props$;
  const vnodeFlags = newVnode.$flags$;
  const elCtx = getContext(elm, containerState);

  if (tag !== VIRTUAL) {
    // Track SVG state
    let isSvg = (flags & IS_SVG) !== 0;
    if (!isSvg && tag === 'svg') {
      flags |= IS_SVG;
      isSvg = true;
    }

    if (props !== EMPTY_OBJ) {
      // elCtx.$vdom$ = newVnode;
      if ((vnodeFlags & static_listeners) === 0) {
        elCtx.li.length = 0;
      }
      const values = oldVnode.$props$;
      newVnode.$props$ = values;
      for (const prop in props) {
        let newValue = props[prop];
        if (prop === 'ref') {
          assertElement(elm);