merger.js

//var sys = require('sys'); // enable for debugging this module
function replace(a, b)
{
 if (!b)
 {
  return a;
 }
 var key;
 for (key in b)
 {
  if(b.hasOwnProperty(key))
  { 
   a[key] = b[key];
  }
 }
   
 return a;
} this.replace=replace;

function add(a, b)
{
 if (!b)
 {
  return a;
 }
 var key;
 for (key in b)
 {
  if(b.hasOwnProperty(key))
  { 
   if(typeof a[key] === 'undefined' ||  a[key]===null)
   {
    a[key] = b[key];
   }
  }
 }
 return a;
} this.add=add;


function extend(a, b, context, newobjs, aparent, aname, haveaparent) // context is anti circular references mechanism
{
 if (a==b){ return a;}
 if (!b)  { return a;}
 
 var key, clean_context=false, return_sublevel=false,b_pos;
 if(!haveaparent){ aparent={'a':a}; aname='a'; }
 if(!context){clean_context=true;context=[];newobjs=[];}
 b_pos=context.indexOf(b);
 if( b_pos==-1 ) {context.push(b);newobjs.push([aparent, aname]);} else { return newobjs[b_pos][0][ newobjs[b_pos][1] ]; }

 for (key in b)
 {
   if(b.hasOwnProperty(key))
   { 
   if(typeof a[key] === 'undefined')
   {
    if(typeof b[key] === 'object')
    {
     if( b[key] instanceof Array ) // http://javascript.crockford.com/remedial.html
      {a[key] = extend([], b[key],context,newobjs,a,key,true);}
     else if(b[key]===null)
      {a[key] = null;}
     else
      {a[key] = extend({}, b[key],context,newobjs,a,key,true); /*a[key].constructor = b[key].constructor;  a[key].prototype = b[key].prototype;*/ }
    }
    else
    {  a[key] = b[key]; }
   }
   else if(typeof a[key] === 'object' && a[key] !== null)
   {  a[key] = extend(a[key], b[key],context,newobjs,a,key,true); /*a[key].constructor = b[key].constructor;  a[key].prototype = b[key].prototype;*/ }
   else  
   {  a[key] = b[key]; }
  }
 }
 if(clean_context) {context=null;newobjs=null;}
 if(!haveaparent)
 {
  aparent=null;
  return a;
 }
 if(typeof a === 'object' && !(a instanceof Array) )
 {
  /*a.constructor = b.constructor;
  a.prototype   = b.prototype*/;
 } 
 return a;
} this.extend=extend;

function extenduptolevel(a, b, levels, context, newobjs, aparent, aname, haveaparent)
{
 if (a==b){ return a;}
 if (!b){ return a;}

 var key, clean_context=false, return_sublevel=false;
 if(!haveaparent){ aparent={'a':a}; aname='a'; }
 if(!context){clean_context=true;context=[];newobjs=[];}
 b_pos=context.indexOf(b);
 if( b_pos==-1 ) {context.push(b);newobjs.push([aparent, aname]);} else { return newobjs[b_pos][0][ newobjs[b_pos][1] ]; }
 
 for (key in b)
 {
  if(b.hasOwnProperty(key))
  { 
   if(typeof a[key] === 'undefined')
   {
    if(typeof b[key] === 'object' && levels>0)
    {
     if( b[key] instanceof Array ) // http://javascript.crockford.com/remedial.html
     { a[key] = extenduptolevel([], b[key],levels-1,context,newobjs,a,key,true); }
     else if(b[key]===null)
     { a[key] = null; }
     else
     { a[key] = extenduptolevel({}, b[key],levels-1,context,newobjs,a,key,true); }
    }
    else
    {  a[key] = b[key]; }
   }
   else if(typeof a[key] === 'object' && a[key] !== null && levels>0)
   {  a[key] = extenduptolevel(a[key], b[key],levels-1,context,newobjs,a,key,true); }
   else  
   {  a[key] = b[key]; }
  }
 }
 if(clean_context) {context=null;newobjs=null;}

 if(!haveaparent)
 {
  aparent=null;
  return a;
 }
 if(typeof a === 'object' && !(a instanceof Array) )
 {
  /*a.constructor = b.constructor;
  a.prototype   = b.prototype;*/
 } 
 return a;
} this.extenduptolevel=extenduptolevel;

function clone(obj)
{
 if (typeof obj === 'object')
 {
  if (obj ===null ) { return null; }
  if (obj instanceof Array )
  { return extend([], obj); }
  else
  { return extend({}, obj); }
 }
 return obj;
} this.clone=clone;

function cloneextend(obj,exteddata)
{
 if (typeof obj === 'object')
 {
  if (obj ===null ) { return null; }
  return extend(clone(obj),exteddata);
 }
 return obj;
} this.cloneextend=cloneextend;


function cloneuptolevel(obj,level) // clone only numlevels levels other levels leave references
{
 if (typeof obj === 'object')
 {
  if (obj ===null ) { return null; }
  if (obj instanceof Array ) { return extenduptolevel([], obj,level); }
  return extenduptolevel({}, obj,level);
 }
 return obj;
} this.cloneuptolevel=cloneuptolevel;


function ObjforEach(object, block, context)
{
 for (var key in object)
 {
  if(object.hasOwnProperty(key))
  {
   block.call(context, object[key], key, object);
  }
 }
}

function foreach(object, block, context)
{
 if (object)
 {
  if (typeof object === "object" && object instanceof Array)
   return object.forEach(object, block, context)
  else //if (typeof object === "object") // or (object instanceof Function)...
  {
   if(object)
   for (var key in object)
   {
    if(object.hasOwnProperty(key))
    {
     block.call(context, object[key], key, object);
    }
   }
  }  
 }
} this.foreach=foreach;

/*
 hasbugs and useless yet interesting maybe developed layer for dot pathed object transformation:
 
 {
  'foo.bar':'bluebar',
  'foo.color':'blue'
 }
 
 transforemed to
 
 {
  foo:
  {
   bar:'bluebar',
   color:'blue'
  }
 }
 //
 function dotpath(data,dotkeys,create)
 {
      if(!create){var create=false;}
      if(create) if(!data) data={};
      var keys= dotkeys.split("."),value=data;
      for (var i=0;i<keys.length;i++)
      {
          if(!value[keys[i]]) //should you create one?
          {
              if(create)
                  value[keys[i]]={};
              else
                  return undefined;
          }
          value = value[keys[i]];
      }
      return value;
 }
 */