/**
 * Normalizes https://developer.mozilla.org/en-US/docs/Web/API/Node/compareDocumentPosition into values usable for Array.prototype.sort.
 */
export function compareDocumentPositionFlat(a: Node, b: Node): 0 | 1 | -1 {
  switch (a.compareDocumentPosition(b) & 2 /* DOCUMENT_POSITION_PRECEDING */) {
    case 0: return 0;     // same element
    case 2: return 1;     // preceding element
    default: return -1;   // assume following element otherwise
  }
}