Function walk

packages/compiler-dom/src/transforms/stringifyStatic.ts:238–290

(node: ElementNode)

  // 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 &&
          !p.exp.isStatic
        ) {
          return bail()
        }
      }
    }
    for (let i = 0; i < node.children.length; i++) {
      nc++
      const child = node.children[i]
      if (child.type === NodeTypes.ELEMENT) {
        if (child.props.length > 0) {
          ec++
        }
        walk(child)
        if (bailed) {
          return false
        }
      }
    }
    return true
  }

  return walk(node) ? [nc, ec] : false
}