Convert javascript objects to xml

toxml.js

// note: no error checking is performed at all
// note: no entity substitution (< and & in particular) is performed

// format an element start tag with optional attributes
// gi is assumed to be a generic identifier
// attlist is assumed to be an associative array indexed by attribute name
// eg { myprop1: "val1", myprop2: "val2" }
var formatStag = function(gi, attlist)
{
   var data = "<" + gi ;

   for (var prop in attlist)
   {
      data = data + formatAttribute(prop, attlist[prop]);
   }

   return( data + ">" );
};

// format an attribute
var formatAttribute = function(attname, attval)
{
   if (!attval) return "";
   return(" " + attname + "='" + attval + "' ");
};

// format an empty element
var formatEElement = function(gi, attlist)
{
   var data;

   data = "<" + gi + " ";

   for (var prop in attlist)
   {
      data = data  + formatAttribute(prop, attlist[prop]);
   }

   return( data + "/>\n" );
};

// format an element end tag
var formatEtag = function(gi)
{
   return("<" + "/" + gi + ">" );
};

// format an element with content
// content is assumed to be well-formed markup
var formatElement = function(gi, attlist, content)
{
   return( formatStag(gi, attlist) + content + formatEtag(gi) + "\n" );
};

// format an element with complex content
// contentobj is assumed to be a JavaScript object which optionally implements a formatXML method
// if present formatXML is assumed to return well formed markup
var formatElementTree = function(gi, attlist, contentobj)
{
   var data = formatStag(gi, attlist);
   if (contentobj.formatXML)
   {
      data = data + contentobj.formatXML() + "\n";
   }
   return( data + formatEtag(gi) );
};

// format a list of elements
// contentobj is assumed to be a JavaScript array of objects that implement a formatXML method
var formatElementList = function(gi, itemenclosure, attlist, contentobj)
{
   var data = formatStag(gi, attlist);
   for (var i=0; i<contentobj.length; ++i) {
     data = data + contentobj[i].formatXML(itemenclosure) + "\n";
   }
   return( data + formatEtag(gi) );
};

// default formatXML
var dflt_formatXML = function(enclosure)
{
   var data = "";

   for (var prop in this)
   {
     if ( this.hasOwnProperty(prop) ) {
       data  = data + formatStag("property") + formatElement("key", null, prop );
       if ( Object.prototype.toString.apply(this[prop]) === '[object Array]' ) {
         console.log("Formatting list");
         data  = data + formatElementList("value", "item", null, this[prop] );
       } else if ( typeof this[prop] == "object" ) {
         data  = data + this[prop].formatXML("value");
       }
       else { 
         data  = data + formatElement("value", null, this[prop]);
       }
       data = data + formatEtag("property");
     }
   }

   if (enclosure) {
    data = formatStag(enclosure)+data+formatEtag(enclosure);
   }

   return(data);
};

var bindToXML = function( constructor ) {
  constructor.prototype.formatXML = dflt_formatXML;
  return( constructor );
};
bindToXML(Object);