React Children API - 가능하지만 비추천

재귀 순회

function traverseReactNode(children: ReactNode, callback, typeToMatch?) {
  Children.forEach(children, (child) => {
    if (!isValidElement(child)) return
    if (child.type === Fragment) {
      traverseReactNode(child.props.children, callback, typeToMatch)
      return
    }
    if (child.type === typeToMatch) callback(child)
    if (child.props?.children) {
      traverseReactNode(child.props.children, callback, typeToMatch)
    }
  })
}

동적 래핑

const renderChildren = (children) => {
  const elements = React.Children.toArray(children)
  const hasLink = elements.some(
    (el) => React.isValidElement(el) && el.props.url
  )
  return hasLink ? children : <ul>{children}</ul>
}
// toArray는 string, number도 포함 → isValidElement 체크 필수

대안: Compound Component

// ❌ 마법처럼 동작 (예측 불가)
<Tabs>{/* 어디에 넣든 Tab 찾아줌 */}</Tabs>

// ✅ Compound Component
<Tabs.Root>
  <Tabs.List>
    <Tabs.Trigger value="a">A</Tabs.Trigger>
  </Tabs.List>
  <Tabs.Content value="a">Content</Tabs.Content>
</Tabs.Root>

React 팀도 2021년부터 Children API 사용 권장하지 않음: “Using Children is uncommon and can lead to fragile code”

역사적 배경: 2013년엔 Context API도 없었음. “선언형”이라면서 Children API로 명령형 트리 순회 제공하는 이중성.

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• react-children-utilities - deepMap, deepFind, deepFilter

react-is로 children에서 특정 컴포넌트 필터링

import * as ReactIs from 'react-is'

// 특정 컴포넌트 타입인지 확인
function isComponentType<T>(element: ReactNode, Type: ComponentType<T>) {
  return ReactIs.isElement(element) && element.type === Type
}

// children에서 특정 컴포넌트만 필터링
function filterChildren<T>(children: ReactNode, Type: ComponentType<T>) {
  return Children.toArray(children).filter(
    (child): child is ReactElement<T> =>
      ReactIs.isElement(child) && child.type === Type
  )
}

// 사용: Layout에서 Header, Content, Footer 분리
const Layout = ({ children }) => {
  const headers = filterChildren(children, Header)
  const contents = filterChildren(children, Content)

  return (
    <div>
      <div className="header">{headers}</div>
      <div className="content">{contents}</div>
    </div>
  )
}