1  /*!
 2   * is-accessor-descriptor <https://github.com/jonschlinkert/is-accessor-descriptor>
 3   *
 4   * Copyright (c) 2015-2017, Jon Schlinkert.
 5   * Released under the MIT License.
 6   */
 7  
 8  'use strict';
 9  
10  var typeOf = require('kind-of');
11  
12  // accessor descriptor properties
13  var accessor = {
14    get: 'function',
15    set: 'function',
16    configurable: 'boolean',
17    enumerable: 'boolean'
18  };
19  
20  function isAccessorDescriptor(obj, prop) {
21    if (typeof prop === 'string') {
22      var val = Object.getOwnPropertyDescriptor(obj, prop);
23      return typeof val !== 'undefined';
24    }
25  
26    if (typeOf(obj) !== 'object') {
27      return false;
28    }
29  
30    if (has(obj, 'value') || has(obj, 'writable')) {
31      return false;
32    }
33  
34    if (!has(obj, 'get') || typeof obj.get !== 'function') {
35      return false;
36    }
37  
38    // tldr: it's valid to have "set" be undefined
39    // "set" might be undefined if `Object.getOwnPropertyDescriptor`
40    // was used to get the value, and only `get` was defined by the user
41    if (has(obj, 'set') && typeof obj[key] !== 'function' && typeof obj[key] !== 'undefined') {
42      return false;
43    }
44  
45    for (var key in obj) {
46      if (!accessor.hasOwnProperty(key)) {
47        continue;
48      }
49  
50      if (typeOf(obj[key]) === accessor[key]) {
51        continue;
52      }
53  
54      if (typeof obj[key] !== 'undefined') {
55        return false;
56      }
57    }
58    return true;
59  }
60  
61  function has(obj, key) {
62    return {}.hasOwnProperty.call(obj, key);
63  }
64  
65  /**
66   * Expose `isAccessorDescriptor`
67   */
68  
69  module.exports = isAccessorDescriptor;