Function replaceSegment

packages/router/src/create_url_tree.ts:223–238

* Replaces the `oldSegment` which is located in some child of the `current` with the `newSegment`. * This also has the effect of creating new `UrlSegmentGroup` copies to update references. This * shouldn't be necessary but the fallback logic for an invalid ActivatedRoute in the creation uses * th

(
  current: UrlSegmentGroup,
  oldSegment: UrlSegmentGroup,
  newSegment: UrlSegmentGroup,
)

 * value.
 */
function replaceSegment(
  current: UrlSegmentGroup,
  oldSegment: UrlSegmentGroup,
  newSegment: UrlSegmentGroup,
): UrlSegmentGroup {
  // Keyed by outlet name, which can be `__proto__`, so use a null-prototype map.
  const children: {[key: string]: UrlSegmentGroup} = Object.create(null);
  Object.entries(current.children).forEach(([outletName, c]) => {
    if (c === oldSegment) {
      children[outletName] = newSegment;
    } else {
      children[outletName] = replaceSegment(c, oldSegment, newSegment);
    }
  });
  return new UrlSegmentGroup(current.segments, children);
}

class Navigation {
  constructor(