1  'use strict';
 2  
 3  // do not edit .js files directly - edit src/index.jst
 4  
 5  
 6  
 7  module.exports = function equal(a, b) {
 8    if (a === b) return true;
 9  
10    if (a && b && typeof a == 'object' && typeof b == 'object') {
11      if (a.constructor !== b.constructor) return false;
12  
13      var length, i, keys;
14      if (Array.isArray(a)) {
15        length = a.length;
16        if (length != b.length) return false;
17        for (i = length; i-- !== 0;)
18          if (!equal(a[i], b[i])) return false;
19        return true;
20      }
21  
22  
23  
24      if (a.constructor === RegExp) return a.source === b.source && a.flags === b.flags;
25      if (a.valueOf !== Object.prototype.valueOf) return a.valueOf() === b.valueOf();
26      if (a.toString !== Object.prototype.toString) return a.toString() === b.toString();
27  
28      keys = Object.keys(a);
29      length = keys.length;
30      if (length !== Object.keys(b).length) return false;
31  
32      for (i = length; i-- !== 0;)
33        if (!Object.prototype.hasOwnProperty.call(b, keys[i])) return false;
34  
35      for (i = length; i-- !== 0;) {
36        var key = keys[i];
37  
38        if (key === '_owner' && a.$$typeof) {
39          // React-specific: avoid traversing React elements' _owner.
40          //  _owner contains circular references
41          // and is not needed when comparing the actual elements (and not their owners)
42          continue;
43        }
44  
45        if (!equal(a[key], b[key])) return false;
46      }
47  
48      return true;
49    }
50  
51    // true if both NaN, false otherwise
52    return a!==a && b!==b;
53  };