1  var isFunction = require('./isFunction'),
 2      isMasked = require('./_isMasked'),
 3      isObject = require('./isObject'),
 4      toSource = require('./_toSource');
 5  
 6  /**
 7   * Used to match `RegExp`
 8   * [syntax characters](http://ecma-international.org/ecma-262/7.0/#sec-patterns).
 9   */
10  var reRegExpChar = /[\\^$.*+?()[\]{}|]/g;
11  
12  /** Used to detect host constructors (Safari). */
13  var reIsHostCtor = /^\[object .+?Constructor\]$/;
14  
15  /** Used for built-in method references. */
16  var funcProto = Function.prototype,
17      objectProto = Object.prototype;
18  
19  /** Used to resolve the decompiled source of functions. */
20  var funcToString = funcProto.toString;
21  
22  /** Used to check objects for own properties. */
23  var hasOwnProperty = objectProto.hasOwnProperty;
24  
25  /** Used to detect if a method is native. */
26  var reIsNative = RegExp('^' +
27    funcToString.call(hasOwnProperty).replace(reRegExpChar, '\\$&')
28    .replace(/hasOwnProperty|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?') + '$'
29  );
30  
31  /**
32   * The base implementation of `_.isNative` without bad shim checks.
33   *
34   * @private
35   * @param {*} value The value to check.
36   * @returns {boolean} Returns `true` if `value` is a native function,
37   *  else `false`.
38   */
39  function baseIsNative(value) {
40    if (!isObject(value) || isMasked(value)) {
41      return false;
42    }
43    var pattern = isFunction(value) ? reIsNative : reIsHostCtor;
44    return pattern.test(toSource(value));
45  }
46  
47  module.exports = baseIsNative;