Function compare

docs/external/js/react.development.js:2319–2323

(a, b)

  }

  function compare(a, b) {
    // Compare sort index first, then task id.
    var diff = a.sortIndex - b.sortIndex;
    return diff !== 0 ? diff : a.id - b.id;
  }

  // TODO: Use symbols?
  var NoPriority = 0;