dist/vuex-orm.esm.js
function (it, S) {
  if (!_isObject(it)) return it;
  var fn, val;
  if (S && typeof (fn = it.toString) == 'function' && !_isObject(val = fn.call(it))) return val;
  if (typeof (fn = it.valueOf) == 'function' && !_isObject(val = fn.call(it))) return val;
  if (!S && typeof (fn = it.toString) == 'function' && !_isObject(val = fn.call(it))) return val;
  throw TypeError("Can't convert object to primitive value");
}
function (it, S) {
  if (!_isObject(it)) return it;
  var fn, val;
  if (S && typeof (fn = it.toString) == 'function' && !_isObject(val = fn.call(it))) return val;
  if (typeof (fn = it.valueOf) == 'function' && !_isObject(val = fn.call(it))) return val;
  if (!S && typeof (fn = it.toString) == 'function' && !_isObject(val = fn.call(it))) return val;
  throw TypeError("Can't convert object to primitive value");
}
function ( it , S ) { if ( ! _isObject ( it ) ) return it ; var fn , val ; if ( S && typeof ( fn = it . toString ) == 'function' && ! _isObject ( val = fn . call ( it ) ) ) return val ; if ( typeof ( fn = it . valueOf ) == 'function' && ! _isObject ( val = fn . call ( it ) ) ) return val ; if ( ! S && typeof ( fn = it . toString ) == 'function' && ! _isObject ( val = fn . call ( it ) ) ) return val ; throw TypeError ( "Can't convert object to primitive value" ) ; }
instead of the ES6 spec version, we didn't implement @@toPrimitive case and the second argument - flag - preferred type is a string
instead of the ES6 spec version we didn t implement