Function analyzeNode

packages/compiler-dom/src/transforms/stringifyStatic.ts:212–293

* for a cached node, analyze it and return: * - false: bailed (contains non-stringifiable props or runtime constant) * - [nc, ec] where * - nc is the number of nodes inside * - ec is the number of element with bindings inside

(node: StringifiableNode)

 *   - ec is the number of element with bindings inside
 */
function analyzeNode(node: StringifiableNode): [number, number] | false {
  if (node.type === NodeTypes.ELEMENT && isNonStringifiable(node.tag)) {
    return false
  }

  // v-once nodes should not be stringified
  if (node.type === NodeTypes.ELEMENT && findDir(node, 'once', true)) {
    return false
  }

  if (node.type === NodeTypes.TEXT_CALL) {
    return [1, 0]
  }

  let nc = 1 // node count
  let ec = node.props.length > 0 ? 1 : 0 // element w/ binding count
  let bailed = false
  const bail = (): false => {
    bailed = true
    return false
  }

  // TODO: check for cases where using innerHTML will result in different
  // output compared to imperative node insertions.
  // probably only need to check for most common case
  // i.e. non-phrasing-content tags inside `<p>`
  function walk(node: ElementNode): boolean {
    const isOptionTag = node.tag === 'option' && node.ns === Namespaces.HTML
    for (let i = 0; i < node.props.length; i++) {
      const p = node.props[i]
      // bail on non-attr bindings
      if (
        p.type === NodeTypes.ATTRIBUTE &&
        !isStringifiableAttr(p.name, node.ns)
      ) {
        return bail()
      }
      if (p.type === NodeTypes.DIRECTIVE && p.name === 'bind') {
        // bail on non-attr bindings
        if (
          p.arg &&
          (p.arg.type === NodeTypes.COMPOUND_EXPRESSION ||
            (p.arg.isStatic && !isStringifiableAttr(p.arg.content, node.ns)))
        ) {
          return bail()
        }
        if (
          p.exp &&
          (p.exp.type === NodeTypes.COMPOUND_EXPRESSION ||
            p.exp.constType < ConstantTypes.CAN_STRINGIFY)
        ) {
          return bail()
        }
        // <option :value="1"> cannot be safely stringified
        if (
          isOptionTag &&
          isStaticArgOf(p.arg, 'value') &&
          p.exp &&