Gist file for comparing two objects

object_compare.js

function deepCompare () {
  var i, l, leftChain, rightChain;

  function compare2Objects (x, y) {
    var p;

    // remember that NaN === NaN returns false
    // and isNaN(undefined) returns true
    if (isNaN(x) && isNaN(y) && typeof x === 'number' && typeof y === 'number') {
         return true;
    }

    // Compare primitives and functions.     
    // Check if both arguments link to the same object.
    // Especially useful on the step where we compare prototypes
    if (x === y) {
        return true;
    }

    // Works in case when functions are created in constructor.
    // Comparing dates is a common scenario. Another built-ins?
    // We can even handle functions passed across iframes
    if ((typeof x === 'function' && typeof y === 'function') ||
       (x instanceof Date && y instanceof Date) ||
       (x instanceof RegExp && y instanceof RegExp) ||
       (x instanceof String && y instanceof String) ||
       (x instanceof Number && y instanceof Number)) {
        return x.toString() === y.toString();
    }

    // At last checking prototypes as good as we can
    if (!(x instanceof Object && y instanceof Object)) {
        return false;
    }

    if (x.isPrototypeOf(y) || y.isPrototypeOf(x)) {
        return false;
    }

    if (x.constructor !== y.constructor) {
        return false;
    }

    if (x.prototype !== y.prototype) {
        return false;
    }

    // Check for infinitive linking loops
    if (leftChain.indexOf(x) > -1 || rightChain.indexOf(y) > -1) {
         return false;
    }

    // Quick checking of one object being a subset of another.
    // todo: cache the structure of arguments[0] for performance
    for (p in y) {
        if (y.hasOwnProperty(p) !== x.hasOwnProperty(p)) {
            return false;
        }
        else if (typeof y[p] !== typeof x[p]) {
            return false;
        }
    }

    for (p in x) {
        if (y.hasOwnProperty(p) !== x.hasOwnProperty(p)) {
            return false;
        }
        else if (typeof y[p] !== typeof x[p]) {
            return false;
        }

        switch (typeof (x[p])) {
            case 'object':
            case 'function':

                leftChain.push(x);
                rightChain.push(y);

                if (!compare2Objects (x[p], y[p])) {
                    return false;
                }

                leftChain.pop();
                rightChain.pop();
                break;

            default:
                if (x[p] !== y[p]) {
                    return false;
                }
                break;
        }
    }

    return true;
  }

  if (arguments.length < 1) {
    return true; //Die silently? Don't know how to handle such case, please help...
    // throw "Need two or more arguments to compare";
  }

  for (i = 1, l = arguments.length; i < l; i++) {

      leftChain = []; //Todo: this can be cached
      rightChain = [];

      if (!compare2Objects(arguments[0], arguments[i])) {
          return false;
      }
  }

  return true;
}

object_compare_min.js

function deepCompare(){function t(e,r){var f;if(isNaN(e)&&isNaN(r)&&"number"==typeof e&&"number"==typeof r)return!0;if(e===r)return!0;if("function"==typeof e&&"function"==typeof r||e instanceof Date&&r instanceof Date||e instanceof RegExp&&r instanceof RegExp||e instanceof String&&r instanceof String||e instanceof Number&&r instanceof Number)return e.toString()===r.toString();if(!(e instanceof Object&&r instanceof Object))return!1;if(e.isPrototypeOf(r)||r.isPrototypeOf(e))return!1;if(e.constructor!==r.constructor)return!1;if(e.prototype!==r.prototype)return!1;if(n.indexOf(e)>-1||o.indexOf(r)>-1)return!1;for(f in r){if(r.hasOwnProperty(f)!==e.hasOwnProperty(f))return!1;if(typeof r[f]!=typeof e[f])return!1}for(f in e){if(r.hasOwnProperty(f)!==e.hasOwnProperty(f))return!1;if(typeof r[f]!=typeof e[f])return!1;switch(typeof e[f]){case"object":case"function":if(n.push(e),o.push(r),!t(e[f],r[f]))return!1;n.pop(),o.pop();break;default:if(e[f]!==r[f])return!1}}return!0}var e,r,n,o;if(arguments.length<1)return!0;for(e=1,r=arguments.length;r>e;e++)if(n=[],o=[],!t(arguments[0],arguments[e]))return!1;return!0}

stackoverflow link for credits

http://stackoverflow.com/a/1144249/3339876

Really useful.