isTagValidWithParent() — react Function Reference

Source Code

packages/react-dom-bindings/src/client/validateDOMNesting.js lines 302–460

function isTagValidWithParent(
  tag: string,
  parentTag: ?string,
  implicitRootScope: boolean,
): boolean {
  // First, let's check if we're in an unusual parsing mode...
  switch (parentTag) {
    // https://html.spec.whatwg.org/multipage/syntax.html#parsing-main-inselect
    case 'select':
      return (
        tag === 'hr' ||
        tag === 'option' ||
        tag === 'optgroup' ||
        tag === 'script' ||
        tag === 'template' ||
        tag === '#text'
      );
    case 'optgroup':
      return tag === 'option' || tag === '#text';
    // Strictly speaking, seeing an <option> doesn't mean we're in a <select>
    // but
    case 'option':
      return tag === '#text';
    // https://html.spec.whatwg.org/multipage/syntax.html#parsing-main-intd
    // https://html.spec.whatwg.org/multipage/syntax.html#parsing-main-incaption
    // No special behavior since these rules fall back to "in body" mode for
    // all except special table nodes which cause bad parsing behavior anyway.

    // https://html.spec.whatwg.org/multipage/syntax.html#parsing-main-intr
    case 'tr':
      return (
        tag === 'th' ||
        tag === 'td' ||
        tag === 'style' ||
        tag === 'script' ||
        tag === 'template'
      );
    // https://html.spec.whatwg.org/multipage/syntax.html#parsing-main-intbody
    case 'tbody':
    case 'thead':
    case 'tfoot':
      return (
        tag === 'tr' ||
        tag === 'style' ||
        tag === 'script' ||
        tag === 'template'
      );
    // https://html.spec.whatwg.org/multipage/syntax.html#parsing-main-incolgroup
    case 'colgroup':
      return tag === 'col' || tag === 'template';
    // https://html.spec.whatwg.org/multipage/syntax.html#parsing-main-intable
    case 'table':
      return (
        tag === 'caption' ||
        tag === 'colgroup' ||
        tag === 'tbody' ||
        tag === 'tfoot' ||
        tag === 'thead' ||
        tag === 'style' ||
        tag === 'script' ||
        tag === 'template'
      );
    // https://html.spec.whatwg.org/multipage/syntax.html#parsing-main-inhead
    case 'head':
      return (
        tag === 'base' ||
        tag === 'basefont' ||
        tag === 'bgsound' ||
        tag === 'link' ||
        tag === 'meta' ||
        tag === 'title' ||
        tag === 'noscript' ||
        tag === 'noframes' ||
        tag === 'style' ||
        tag === 'script' ||
        tag === 'template'
      );
    // https://html.spec.whatwg.org/multipage/semantics.html#the-html-element
    case 'html':
      if (implicitRootScope) {
        // When our parent tag is html and we're in the root scope we will actually