array-equal.js

Array.isEqual = function(a, b) {
  if (a === b) {
    return true;
  }
  // We do not expect string arguments
  if (typeof a === 'string' || typeof b === 'string') {
    return false;
  }
  
  // We need array like arguments (e.g. NodeList)
  // That is why we don't check for explicitly Array type
  if ((a && !a.length) || (b && !b.length) || a.length !== b.length) {
    return false;
  }
  
  a = this.prototype.slice.call(a);
  b = this.prototype.slice.call(b);
  var i = -1; 
  
  while (++i < a.length) { 
    var currentItem = a[i];
    var haveEqualItemCount = function() {
      var compareFilter = function() {
        if (typeof item !== 'string' && item.length 
          && typeof currentItem !== 'string' && currentItem.length) {
            return this.isEqual(item, currentItem);
        }
        
        return item === currentItem;
      };
      return (a.filter(compareFilter).length === b.filter(compareFilter).length);
    };
    
    // Current item found (works for string, numbers and objects by reference)
    if (b.indexOf(currentItem) > -1) {
      continue;
    }
    // Otherwise if currentItem can not be found using indexOf
    // We have a different object or we need to compare arrays
    for (var j = 0; j < b.length; j++) {
      // When both are array like (e.g Nodelist, arguments etc.)
      if (typeof b[j] !== 'string' && b[j].length 
          && typeof currentItem !== 'string' && currentItem.length) {
        if (!this.isEqual(b[j], currentItem)) return false;
      }  
    }
    
    if (!haveEqualItemCount()) return false;  
  } 
  
  return true;
}