function formatEqlResult(r, a, b) {
  return ((r.path.length > 0
    ? "at " + r.path.map(formatProp).join(" -> ")
    : "") +
    (r.a === a ? "" : ", A has " + format$2(r.a)) +
    (r.b === b ? "" : " and B has " + format$2(r.b)) +
    (r.showReason ? " because " + r.reason : "")).trim();
}
Assert given object is a generator object
@name generator
@memberOf Assertion
@category assertion es6