build/web/c0.js
function isAncestorIDOf(ancestorID, descendantID) {
  return (
    descendantID.indexOf(ancestorID) === 0 &&
    isBoundary(descendantID, ancestorID.length)
  );
}
function isAncestorIDOf(ancestorID, descendantID) {
  return (
    descendantID.indexOf(ancestorID) === 0 &&
    isBoundary(descendantID, ancestorID.length)
  );
}
function isAncestorIDOf ( ancestorID , descendantID ) { return ( descendantID . indexOf ( ancestorID ) === 0 && isBoundary ( descendantID , ancestorID . length ) ) ; }
Checks if the first ID is an ancestor of or equal to the second ID.

@param {string} ancestorID
@param {string} descendantID
@return {boolean} True if `ancestorID` is an ancestor of `descendantID`.
@internal
Checks if the first ID is an ancestor of or equal to the second ID .