restoreSelection() — react Function Reference

Source Code

packages/react-dom-bindings/src/client/ReactInputSelection.js lines 120–155

export function restoreSelection(priorSelectionInformation, containerInfo) {
  const curFocusedElem = getActiveElementDeep(containerInfo);
  const priorFocusedElem = priorSelectionInformation.focusedElem;
  const priorSelectionRange = priorSelectionInformation.selectionRange;
  if (curFocusedElem !== priorFocusedElem && isInDocument(priorFocusedElem)) {
    if (
      priorSelectionRange !== null &&
      hasSelectionCapabilities(priorFocusedElem)
    ) {
      setSelection(priorFocusedElem, priorSelectionRange);
    }

    // Focusing a node can change the scroll position, which is undesirable
    const ancestors = [];
    let ancestor = priorFocusedElem;
    while ((ancestor = ancestor.parentNode)) {
      if (ancestor.nodeType === ELEMENT_NODE) {
        ancestors.push({
          element: ancestor,
          left: ancestor.scrollLeft,
          top: ancestor.scrollTop,
        });
      }
    }

    if (typeof priorFocusedElem.focus === 'function') {
      priorFocusedElem.focus();
    }

    for (let i = 0; i < ancestors.length; i++) {
      const info = ancestors[i];
      info.element.scrollLeft = info.left;
      info.element.scrollTop = info.top;
    }
  }
}