@carbon/ibm-products
Version:
Carbon for IBM Products
65 lines (63 loc) • 2.21 kB
JavaScript
/**
* Copyright IBM Corp. 2020, 2026
*
* This source code is licensed under the Apache-2.0 license found in the
* LICENSE file in the root directory of this source tree.
*/
//#region src/components/PageHeader/next/utils.ts
/**
* Copyright IBM Corp. 2025
*
* This source code is licensed under the Apache-2.0 license found in the
* LICENSE file in the root directory of this source tree.
*/
/**
* ----------
* Utilities
* ----------
*/
const getHeaderOffset = (el) => {
const scrollableContainer = scrollableAncestor(el);
const offsetMeasuringTop = el ? el.getBoundingClientRect().top : 0;
if (scrollableContainer === document.scrollingElement) return offsetMeasuringTop >= 0 ? offsetMeasuringTop : 0;
else {
const scrollableContainerTop = scrollableContainer ? scrollableContainer.getBoundingClientRect().top : 0;
const totalHeaderOffset = offsetMeasuringTop !== 0 ? offsetMeasuringTop - scrollableContainerTop : 0;
return totalHeaderOffset >= 0 ? totalHeaderOffset : 0;
}
};
const windowExists = typeof window !== `undefined`;
/**
* Determines if the given target is scrollable
*
* @param {HTMLElement} target
* @returns {boolean}
*/
const scrollable = (target) => {
const style = window.getComputedStyle(target);
const tagName = target.tagName.toLowerCase();
if (tagName === "body" || tagName === "html") return /(auto|scroll)/.test(style.overflow);
return /(auto|scroll|hidden)/.test(style.overflow);
};
/**
* Recursively looks for the scrollable ancestor
*/
const scrollableAncestorInner = (target) => {
if (target.parentNode && target.parentNode !== document) if (scrollable(target.parentNode)) return target.parentNode;
else return scrollableAncestorInner(target.parentNode);
else return document.scrollingElement;
};
/**
* Walks up the parent nodes to identify the first scrollable ancestor
*
* @param {HTMLElement} target
* @returns {HTMLElement}
*/
const scrollableAncestor = (target) => {
if (!windowExists || !target) return null;
const style = window.getComputedStyle(target);
if (!target || !style || style.position === "fixed") return document.scrollingElement;
return scrollableAncestorInner(target);
};
//#endregion
export { getHeaderOffset, scrollableAncestor };