FezVrasta/popper.js

type OverflowAncestors = Array<Element | Window | VisualViewport>;

export function getNodeName(node: Node | Window): string {
  if (isNode(node)) {
    return (node.nodeName || '').toLowerCase();
  }
  // Mocked nodes in testing environments may not be instances of Node. By
  // returning `#document` an infinite loop won't occur.
  // https://github.com/floating-ui/floating-ui/issues/2317
  return '#document';
}

export function getWindow(node: any): typeof window {
  return node?.ownerDocument?.defaultView || window;
}

export function getDocumentElement(node: Node | Window): HTMLElement {
  return (
    (isNode(node) ? node.ownerDocument : node.document) || window.document
  )?.documentElement;
}

export function isNode(value: unknown): value is Node {
  return value instanceof Node || value instanceof getWindow(value).Node;
}

export function isElement(value: unknown): value is Element {
  return value instanceof Element || value instanceof getWindow(value).Element;
}

export function isHTMLElement(value: unknown): value is HTMLElement {
  return (
    value instanceof HTMLElement ||
    value instanceof getWindow(value).HTMLElement
  );
}

export function isShadowRoot(value: unknown): value is ShadowRoot {
  // Browsers without `ShadowRoot` support.
  if (typeof ShadowRoot === 'undefined') {
    return false;
  }

  return (
    value instanceof ShadowRoot || value instanceof getWindow(value).ShadowRoot
  );
}

export function isOverflowElement(element: Element): boolean {
  const {overflow, overflowX, overflowY, display} = getComputedStyle(element);
  return (
    /auto|scroll|overlay|hidden|clip/.test(overflow + overflowY + overflowX) &&
    !['inline', 'contents'].includes(display)
  );
}

export function isTableElement(element: Element): boolean {
  return ['table', 'td', 'th'].includes(getNodeName(element));
}

export function isContainingBlock(element: Element): boolean {
  const webkit = isWebKit();
  const css = getComputedStyle(element);

  // https://developer.mozilla.org/en-US/docs/Web/CSS/Containing_block#identifying_the_containing_block
  return (
    css.transform !== 'none' ||
    css.perspective !== 'none' ||
    (css.containerType ? css.containerType !== 'normal' : false) ||
    (!webkit && (css.backdropFilter ? css.backdropFilter !== 'none' : false)) ||
    (!webkit && (css.filter ? css.filter !== 'none' : false)) ||
    ['transform', 'perspective', 'filter'].some((value) =>
      (css.willChange || '').includes(value),
    ) ||
    ['paint', 'layout', 'strict', 'content'].some((value) =>
      (css.contain || '').includes(value),
    )
  );
}

export function getContainingBlock(element: Element): HTMLElement | null {
  let currentNode: Node | null = getParentNode(element);

  while (isHTMLElement(currentNode) && !isLastTraversableNode(currentNode)) {
    if (isContainingBlock(currentNode)) {
      return currentNode;
    }

    currentNode = getParentNode(currentNode);
  }

  return null;
}

export function isWebKit(): boolean {
  if (typeof CSS === 'undefined' || !CSS.supports) return false;
  return CSS.supports('-webkit-backdrop-filter', 'none');
}

export function isLastTraversableNode(node: Node): boolean {
  return ['html', 'body', '#document'].includes(getNodeName(node));
}

export function getComputedStyle(element: Element): CSSStyleDeclaration {
  return getWindow(element).getComputedStyle(element);
}

export function getNodeScroll(element: Element | Window): {
  scrollLeft: number;
  scrollTop: number;
} {
  if (isElement(element)) {
    return {
      scrollLeft: element.scrollLeft,
      scrollTop: element.scrollTop,
    };
  }

  return {
    scrollLeft: element.pageXOffset,
    scrollTop: element.pageYOffset,
  };
}

export function getParentNode(node: Node): Node {
  if (getNodeName(node) === 'html') {
    return node;
  }

  const result =
    // Step into the shadow DOM of the parent of a slotted node.
    (node as any).assignedSlot ||
    // DOM Element detected.
    node.parentNode ||
    // ShadowRoot detected.
    (isShadowRoot(node) && node.host) ||
    // Fallback.
    getDocumentElement(node);

  return isShadowRoot(result) ? result.host : result;
}

export function getNearestOverflowAncestor(node: Node): HTMLElement {
  const parentNode = getParentNode(node);

  if (isLastTraversableNode(parentNode)) {
    return node.ownerDocument
      ? node.ownerDocument.body
      : (node as Document).body;
  }

  if (isHTMLElement(parentNode) && isOverflowElement(parentNode)) {
    return parentNode;
  }

  return getNearestOverflowAncestor(parentNode);
}

export function getOverflowAncestors(
  node: Node,
  list: OverflowAncestors = [],
  traverseIframes = true,
): OverflowAncestors {
  const scrollableAncestor = getNearestOverflowAncestor(node);
  const isBody = scrollableAncestor === node.ownerDocument?.body;
  const win = getWindow(scrollableAncestor);

  if (isBody) {
    return list.concat(
      win,
      win.visualViewport || [],
      isOverflowElement(scrollableAncestor) ? scrollableAncestor : [],
      win.frameElement && traverseIframes
        ? getOverflowAncestors(win.frameElement)
        : [],
    );
  }

  return list.concat(
    scrollableAncestor,
    getOverflowAncestors(scrollableAncestor, [], traverseIframes),
  );
}