start of bidi conversion between js<-->xml

js2xml.js

var util = require('util')
  , fs = require('fs')
  , xml2js = require('xml2js-expat')
  , querystring = require('querystring')
  , _ = require('underscore');

// this is provided by xml2js
function parse(xmlString, cb) {
  var parser = new xml2js.Parser();
  parser.on('end', function(result) {
    cb(null, result);
  });
  parser.on('error', function(err) {
    cb(err);
  });
  parser.parseString(xmlString);
}

// this is what I need to write.
function format(object, parent) {
  return formatHelper(object, parent, '\n');
}

function formatHelper(object, parent, tabs) {
  if (object) {
    var xml = ''
      , prenewline = false;
    
    xml += tabs + '<' + parent;
    if (object['@']) {
      xml += ' ' + querystring.stringify(object['@'], '" ', '="') + '"';
      prenewline = true;
    }
    xml += '>';
    delete object['@'];
    
    for (var k in object) {
      var v = object[k];
      
      if (_.isArray(v)) {
        v.forEach(function(el) {
          xml += formatHelper(el, k, tabs + '\t');
        });
        
      } else if (_.isString(object)) {
        var str = object;
        xml += str; //formatHelper(null, parent, tabs + '\n\t');
        prenewline = false;
        
      } else if (k == '#') {
        xml += v;
        prenewline = false;
        
      } else {
        xml += formatHelper(v, k, tabs+'\t');
        prenewline = true;
      }
      xml += (prenewline) ? tabs : '';
      xml += '</' + parent + '>';
      return xml;
    }
    
  } else { // should never get here.
    console.log('--err', object, parent);
    return '';
  }
}

// reading xml and looking at it, so we can base the xml2js on this.
fs.readFile('test.xml', 'utf8', function(err, xmlString) {
  console.log('==xml==');
  console.log(xmlString);
  console.log();

  parse(xmlString, function(err, object) {
    if (err) console.log(err);
    
    console.log('==xml2js==');
    console.log(util.inspect(object, false, null));
    console.log();
    
    console.log('==xmlString==');
    var xml = format(object, 'directededge');
    console.log(xml);
    
    // let's see if we did shit right!
    parse(xml, function(err, test) {
      console.log('worked? (mine then theirs)');
      console.log('this should work, but it doesn\'t, oops');
      console.log(util.inspect(test, false, null));
      console.log(util.inspect(object, false, null));
    });
    
  });
});


// var object = 
// { '@': { version: '0.1', test: 'ohai' },
//   item: 
//    [ { '@': { id: 'customer1' },
//        link: 
//         [ 'product1',
//           'product2',
//           { '#': 'product3', '@': { ohnice: 'test' } } ] },
//      { '@': { id: 'customer2', ohnice: 'test' },
//        tag: 'customer' },
//      { '@': { id: 'customer3' }, link: 'product3' },
//      { '@': { id: 'product1' }, tag: 'product' },
//      { '@': { id: 'product2' }, tag: 'product' },
//      { '@': { id: 'product3' }, tag: 'product' } ] };
     
// three cases
  // hit object
  // hit array
  // hit string
     

test.xml

<directededge version="0.1" test="ohai">
  
  <item id="customer1">
    <link>product1</link>
    <link>product2</link>
    <link ohnice="test">product3</link>
  </item>
  <item id="customer2" ohnice="test">
    <tag>customer</tag>
  </item>
  <item id="customer3">
    <link>product3</link>
  </item>
  
  <item id="product1">
    <tag>product</tag>
  </item>
  <item id="product2">
    <tag>product</tag>
  </item>
  <item id="product3">
    <tag>product</tag>
  </item>

</directededge>