jasmine/src/core/matchersUtil.js

getJasmineRequireObj().matchersUtil = function(j$) {
  // TODO: what to do about jasmine.pp not being inject? move to JSON.stringify? gut PrettyPrinter?

  return {
    equals: function(a, b, customTesters) {
      customTesters = customTesters || [];

      return eq(a, b, [], [], customTesters);
    },

    contains: function(haystack, needle, customTesters) {
      customTesters = customTesters || [];

      if (Object.prototype.toString.apply(haystack) === "[object Array]") {
        for (var i = 0; i < haystack.length; i++) {
          if (eq(haystack[i], needle, [], [], customTesters)) {
            return true;
          }
        }
        return false;
      }
      return haystack.indexOf(needle) >= 0;
    },

    buildFailureMessage: function() {
      var args = Array.prototype.slice.call(arguments, 0),
        matcherName = args[0],
        isNot = args[1],
        actual = args[2],
        expected = args.slice(3),
        englishyPredicate = matcherName.replace(/[A-Z]/g, function(s) { return ' ' + s.toLowerCase(); });

      var message = "Expected " +
        j$.pp(actual) +
        (isNot ? " not " : " ") +
        englishyPredicate;

      if (expected.length > 0) {
        for (var i = 0; i < expected.length; i++) {
          if (i > 0) message += ",";
          message += " " + j$.pp(expected[i]);
        }
      }

      return message + ".";
    }
  };

  // Equality function lovingly adapted from isEqual in
  //   [Underscore](http://underscorejs.org)
  function eq(a, b, aStack, bStack, customTesters) {
    var result = true;

    for (var i = 0; i < customTesters.length; i++) {
      result = customTesters[i](a, b);
      if (result) {
        return true;
      }
    }

    if (a instanceof j$.Any) {
      result = a.jasmineMatches(b);
      if (result) {
        return true;
      }
    }

    if (b instanceof j$.Any) {
      result = b.jasmineMatches(a);
      if (result) {
        return true;
      }
    }

    if (b instanceof j$.ObjectContaining) {
      result = b.jasmineMatches(a);
      if (result) {
        return true;
      }
    }



    // Identical objects are equal. `0 === -0`, but they aren't identical.
    // See the [Harmony `egal` proposal](http://wiki.ecmascript.org/doku.php?id=harmony:egal).
    if (a === b) return a !== 0 || 1 / a == 1 / b;
    // A strict comparison is necessary because `null == undefined`.
    if (a === null || b === null) return a === b;
    var className = Object.prototype.toString.call(a);
    if (className != Object.prototype.toString.call(b)) return false;
    switch (className) {
      // Strings, numbers, dates, and booleans are compared by value.
      case '[object String]':
        // Primitives and their corresponding object wrappers are equivalent; thus, `"5"` is
        // equivalent to `new String("5")`.
        return a == String(b);
      case '[object Number]':
        // `NaN`s are equivalent, but non-reflexive. An `egal` comparison is performed for
        // other numeric values.
        return a != +a ? b != +b : (a === 0 ? 1 / a == 1 / b : a == +b);
      case '[object Date]':
      case '[object Boolean]':
        // Coerce dates and booleans to numeric primitive values. Dates are compared by their
        // millisecond representations. Note that invalid dates with millisecond representations
        // of `NaN` are not equivalent.
        return +a == +b;
      // RegExps are compared by their source patterns and flags.
      case '[object RegExp]':
        return a.source == b.source &&
          a.global == b.global &&
          a.multiline == b.multiline &&
          a.ignoreCase == b.ignoreCase;
    }
    if (typeof a != 'object' || typeof b != 'object') return false;
    // Assume equality for cyclic structures. The algorithm for detecting cyclic
    // structures is adapted from ES 5.1 section 15.12.3, abstract operation `JO`.
    var length = aStack.length;
    while (length--) {
      // Linear search. Performance is inversely proportional to the number of
      // unique nested structures.
      if (aStack[length] == a) return bStack[length] == b;
    }
    // Add the first object to the stack of traversed objects.
    aStack.push(a);
    bStack.push(b);
    var size = 0;
    // Recursively compare objects and arrays.
    if (className == '[object Array]') {
      // Compare array lengths to determine if a deep comparison is necessary.
      size = a.length;
      result = size == b.length;
      if (result) {
        // Deep compare the contents, ignoring non-numeric properties.
        while (size--) {
          if (!(result = eq(a[size], b[size], aStack, bStack, customTesters))) break;
        }
      }
    } else {
      // Objects with different constructors are not equivalent, but `Object`s
      // from different frames are.
      var aCtor = a.constructor, bCtor = b.constructor;
      if (aCtor !== bCtor && !(isFunction(aCtor) && (aCtor instanceof aCtor) &&
        isFunction(bCtor) && (bCtor instanceof bCtor))) {
        return false;
      }
      // Deep compare objects.
      for (var key in a) {
        if (has(a, key)) {
          // Count the expected number of properties.
          size++;
          // Deep compare each member.
          if (!(result = has(b, key) && eq(a[key], b[key], aStack, bStack, customTesters))) break;
        }
      }
      // Ensure that both objects contain the same number of properties.
      if (result) {
        for (key in b) {
          if (has(b, key) && !(size--)) break;
        }
        result = !size;
      }
    }
    // Remove the first object from the stack of traversed objects.
    aStack.pop();
    bStack.pop();

    return result;

    function has(obj, key) {
      return obj.hasOwnProperty(key);
    }

    function isFunction(obj) {
      return typeof obj === 'function';
    }
  }
};