parser.js

var fs = require('fs');
var http = require('http');

if(!Array.prototype.last) {
  Array.prototype.last = function() {
    return this[this.length - 1];
  };
}

http.createServer(function(req, res) {

  fs.readFile('./mock.json', 'utf-8', function(err, mockData) {
    if(err) throw err;
    var mock = JSON.parse(mockData);
    var production = [];
    var oldCategory = '';
    var oldSection = '';

    mock.forEach(function(what) {
      what.expression.replace(/([^=]*)=(.*)/, function(match, exp, value) {
        what.exp = exp;
        what.value = value;
      });

      var currentCategory = what.category;
      var currentSection = what.section;

      if(currentCategory === oldCategory) {
        if(currentSection === oldSection) {
          this.last().section.last().items.push({
            name: what.item,
            value: what.value
          });
        } else {
          this.last().section.push({
            name: what.section,
            items: [
              {name: what.item, value: what.value}
            ]
          });
          oldSection = currentSection;
        }
      } else {
        this.push({
          category: what.category,
          section: [{
            name: what.section,
            items: [
              { name: what.item, value: what.value }
            ]
          }]
        });
        oldCategory = currentCategory;
        oldSection = currentSection;
      }
    }, production);

    res.writeHead(200, {'Content-Type': 'application/json'});
    res.end(JSON.stringify(production));

  });

}).listen(9009, '127.0.0.1');