Function isPlainObject

lib/utils.js:186–202

(val)

 * @returns {boolean} True if value is a plain Object, otherwise false
 */
const isPlainObject = (val) => {
  if (!isObject(val)) {
    return false;
  }

  const prototype = getPrototypeOf(val);
  return (
    (prototype === null ||
      prototype === Object.prototype ||
      getPrototypeOf(prototype) === null) &&
    // Treat any genuine (non-Object.prototype-polluted) Symbol.toStringTag or
    // Symbol.iterator as evidence the value is a tagged/iterable type rather
    // than a plain object, while ignoring keys injected onto Object.prototype.
    !hasOwnInPrototypeChain(val, toStringTag) &&
    !hasOwnInPrototypeChain(val, iterator)
  );
};

/**
 * Determine if a value is an empty object (safely handles Buffers)