Rekord

Source: functions/comparison.js

  2. /**
  3.  * A function for comparing two values and determine whether they're considered
  4.  * equal.
  5.  *
  6.  * @callback equalityCallback
  7.  * @param {Any} a -
  8.  *    The first value to test.
  9.  * @param {Any} b -
  10.  *    The second value to test.
  11.  * @return {Boolean} -
  12.  *    Whether or not the two values are considered equivalent.
  13.  * @see Rekord.equals
  14.  * @see Rekord.equalsStrict
  15.  * @see Rekord.equalsCompare
  16.  */
  18.  /**
  19.   * A function for comparing two values to determine if one is greater or lesser
  20.   * than the other or if they're equal.
  21.   *
  22.   * ```javascript
  23.   * comparisonCallback( a, b ) < 0 // a < b
  24.   * comparisonCallback( a, b ) > 0 // a > b
  25.   * comparisonCallback( a, b ) == 0 // a == b
  26.   * ```
  27.   *
  28.   * @callback comparisonCallback
  29.   * @param {Any} a -
  30.   *    The first value to test.
  31.   * @param {Any} b -
  32.   *    The second value to test.
  33.   * @return {Number} -
  34.   *    0 if the two values are considered equal, a negative value if `a` is
  35.   *    considered less than `b`, and a positive value if `a` is considered
  36.   *    greater than `b`.
  37.   * @see Rekord.compare
  38.   * @see Rekord.compareNumbers
  39.   */
  41. function equalsStrict(a, b)
  42. {
  43.   return a === b;
  44. }
  46. function equalsCompare(a, b)
  47. {
  48.   return compare( a, b ) === 0;
  49. }
  51. function equals(a, b)
  52. {
  53.   if (a === b)
  54.   {
  55.     return true;
  56.   }
  57.   if (a === null || b === null)
  58.   {
  59.     return false;
  60.   }
  61.   if (a !== a && b !== b)
  62.   {
  63.     return true; // NaN === NaN
  64.   }
  66.   var at = typeof a;
  67.   var bt = typeof b;
  68.   var ar = isRegExp(a);
  69.   var br = isRegExp(b);
  71.   if (at === 'string' && br)
  72.   {
  73.     return b.test(a);
  74.   }
  75.   if (bt === 'string' && ar)
  76.   {
  77.     return a.test(b);
  78.   }
  80.   if (at !== bt)
  81.   {
  82.     return false;
  83.   }
  85.   var aa = isArray(a);
  86.   var ba = isArray(b);
  87.   if (aa !== ba)
  88.   {
  89.     return false;
  90.   }
  92.   if (aa)
  93.   {
  94.     if (a.length !== b.length)
  95.     {
  96.       return false;
  97.     }
  99.     for (var i = 0; i < a.length; i++)
  100.     {
  101.       if (!equals(a[i], b[i]))
  102.       {
  103.         return false;
  104.       }
  105.     }
  107.     return true;
  108.   }
  110.   if (isDate(a))
  111.   {
  112.     return isDate(b) && equals( a.getTime(), b.getTime() );
  113.   }
  114.   if (ar)
  115.   {
  116.     return br && a.toString() === b.toString();
  117.   }
  119.   if (at === 'object')
  120.   {
  121.     for (var ap in a)
  122.     {
  123.       if (ap.charAt(0) !== '$' && !isFunction(a[ap]))
  124.       {
  125.         if (!(ap in b) || !equals(a[ap], b[ap]))
  126.         {
  127.           return false;
  128.         }
  129.       }
  130.     }
  132.     for (var bp in b)
  133.     {
  134.       if (bp.charAt(0) !== '$' && !isFunction(b[bp]))
  135.       {
  136.         if (!(bp in a))
  137.         {
  138.           return false;
  139.         }
  140.       }
  141.     }
  143.     return true;
  144.   }
  146.   return false;
  147. }
  149. function compareNumbers(a, b)
  150. {
  151.   return (a === b ? 0 : (a < b ? -1 : 1));
  152. }
  154. function compare(a, b, nullsFirst)
  155. {
  156.   if (a == b) // jshint ignore:line
  157.   {
  158.     return 0;
  159.   }
  161.   var av = isValue( a );
  162.   var bv = isValue( b );
  164.   if (av !== bv)
  165.   {
  166.     return (av && !nullsFirst) || (bv && nullsFirst) ? -1 : 1;
  167.   }
  169.   if (isDate(a))
  170.   {
  171.     a = a.getTime();
  172.   }
  173.   if (isDate(b))
  174.   {
  175.     b = b.getTime();
  176.   }
  177.   if (isNumber(a) && isNumber(b))
  178.   {
  179.     return compareNumbers(a, b);
  180.   }
  181.   if (isArray(a) && isArray(b))
  182.   {
  183.     return compareNumbers(a.length, b.length);
  184.   }
  185.   if (isBoolean(a) && isBoolean(b))
  186.   {
  187.     return (a ? -1 : 1);
  188.   }
  190.   return (a + '').localeCompare(b + '');
  191. }