_arrayLikeKeys.js
 1  var baseTimes = require('./_baseTimes'),
 2      isArguments = require('./isArguments'),
 3      isArray = require('./isArray'),
 4      isBuffer = require('./isBuffer'),
 5      isIndex = require('./_isIndex'),
 6      isTypedArray = require('./isTypedArray');
 7  
 8  /** Used for built-in method references. */
 9  var objectProto = Object.prototype;
10  
11  /** Used to check objects for own properties. */
12  var hasOwnProperty = objectProto.hasOwnProperty;
13  
14  /**
15   * Creates an array of the enumerable property names of the array-like `value`.
16   *
17   * @private
18   * @param {*} value The value to query.
19   * @param {boolean} inherited Specify returning inherited property names.
20   * @returns {Array} Returns the array of property names.
21   */
22  function arrayLikeKeys(value, inherited) {
23    var isArr = isArray(value),
24        isArg = !isArr && isArguments(value),
25        isBuff = !isArr && !isArg && isBuffer(value),
26        isType = !isArr && !isArg && !isBuff && isTypedArray(value),
27        skipIndexes = isArr || isArg || isBuff || isType,
28        result = skipIndexes ? baseTimes(value.length, String) : [],
29        length = result.length;
30  
31    for (var key in value) {
32      if ((inherited || hasOwnProperty.call(value, key)) &&
33          !(skipIndexes && (
34             // Safari 9 has enumerable `arguments.length` in strict mode.
35             key == 'length' ||
36             // Node.js 0.10 has enumerable non-index properties on buffers.
37             (isBuff && (key == 'offset' || key == 'parent')) ||
38             // PhantomJS 2 has enumerable non-index properties on typed arrays.
39             (isType && (key == 'buffer' || key == 'byteLength' || key == 'byteOffset')) ||
40             // Skip index properties.
41             isIndex(key, length)
42          ))) {
43        result.push(key);
44      }
45    }
46    return result;
47  }
48  
49  module.exports = arrayLikeKeys;