Function isKey

src/helpers/set.js:631–650

* Checks if `value` is a property name and not a property path. * * @private * @param {*} value The value to check. * @param {Object} [object] The object to query keys on. * @returns {boolean} Returns `true` if `value` is a property name, else `false`.

(value, object)

 * @returns {boolean} Returns `true` if `value` is a property name, else `false`.
 */
function isKey(value, object) {
  if (isArray(value)) {
    return false;
  }
  var type = typeof value;
  if (
    type == 'number' ||
    type == 'symbol' ||
    type == 'boolean' ||
    value == null ||
    isSymbol(value)
  ) {
    return true;
  }
  return (
    reIsPlainProp.test(value) ||
    !reIsDeepProp.test(value) ||
    (object != null && value in Object(object))
  );
}

/**
 * Checks if `value` is suitable for use as unique object key.