index.js

/*!
 * is-data-descriptor <https://github.com/jonschlinkert/is-data-descriptor>
 *
 * Copyright (c) 2015-2017, Jon Schlinkert.
 * Released under the MIT License.
 */

'use strict';

var typeOf = require('kind-of');

module.exports = function isDataDescriptor(obj, prop) {
  // data descriptor properties
  var data = {
    configurable: 'boolean',
    enumerable: 'boolean',
    writable: 'boolean'
  };

  if (typeOf(obj) !== 'object') {
    return false;
  }

  if (typeof prop === 'string') {
    var val = Object.getOwnPropertyDescriptor(obj, prop);
    return typeof val !== 'undefined';
  }

  if (!('value' in obj) && !('writable' in obj)) {
    return false;
  }

  for (var key in obj) {
    if (key === 'value') continue;

    if (!data.hasOwnProperty(key)) {
      continue;
    }

    if (typeOf(obj[key]) === data[key]) {
      continue;
    }

    if (typeof obj[key] !== 'undefined') {
      return false;
    }
  }
  return true;
};