How to use the terraform.helpers function in terraform

exports.process = function(req, rsp, next){
  var normalizedPath  = helpers.normalizeUrl(req.url)
  var priorityList    = terraform.helpers.buildPriorityList(normalizedPath)
  var sourceFile      = terraform.helpers.findFirstFile(req.setup.publicPath, priorityList)


  /**
   * We GTFO if we don't have a source file.
   */

  if(!sourceFile){
    if (path.basename(normalizedPath) === "index.html") {
      var pathAr = normalizedPath.split(path.sep); pathAr.pop() // Pop index.html off the list
      var prospectCleanPath       = pathAr.join("/")
      var prospectNormalizedPath  = helpers.normalizeUrl(prospectCleanPath)
      var prospectPriorityList    = terraform.helpers.buildPriorityList(prospectNormalizedPath)
      prospectPriorityList.push(path.basename(prospectNormalizedPath + ".html"))

      sourceFile = terraform.helpers.findFirstFile(req.setup.publicPath, prospectPriorityList)

skin(req, rsp, [poly], function(){
    var priorityList  = terraform.helpers.buildPriorityList("200.html")
    var sourceFile    = terraform.helpers.findFirstFile(req.setup.publicPath, priorityList)
    if(!sourceFile) return next()

    req.poly.render(sourceFile, function(error, body){
      if(error){
        // TODO: make this better
        rsp.statusCode = 404;
        rsp.end("There is an error in your " + sourceFile + " file")
      }else{
        if(!body) return next()
        var type    = helpers.mimeType("html")
        var charset = mime.charsets.lookup(type)
        rsp.setHeader('Content-Type', type + (charset ? '; charset=' + charset : ''));
        rsp.setHeader('Content-Length', Buffer.byteLength(body, charset));
        rsp.statusCode = 200;
        rsp.end(body)
      }

terra.render(sourceFile, function(error, body){
      if(error) return next(error)
      if(!body) return next() // 404

      var outputType = terraform.helpers.outputType(sourceFile)
      var mimeType   = helpers.mimeType(outputType)
      var charset    = mime.charsets.lookup(mimeType)
      rsp.statusCode = 200
      rsp.setHeader('Content-Type', mimeType + (charset ? '; charset=' + charset : ''))
      rsp.setHeader('Content-Length', Buffer.byteLength(body, charset));
      rsp.end(body)
    })

return function(req, rsp, next){
    var normalizedPath  = helpers.normalizeUrl(req.url)
    var priorityList    = terraform.helpers.buildPriorityList(normalizedPath)
    var sourceFile      = terraform.helpers.findFirstFile(publicPath, priorityList)

    if(!sourceFile) return next()

    terra.render(sourceFile, function(error, body){
      if(error) return next(error)
      if(!body) return next() // 404

      var outputType = terraform.helpers.outputType(sourceFile)
      var mimeType   = helpers.mimeType(outputType)
      var charset    = mime.charsets.lookup(mimeType)
      rsp.statusCode = 200
      rsp.setHeader('Content-Type', mimeType + (charset ? '; charset=' + charset : ''))
      rsp.setHeader('Content-Length', Buffer.byteLength(body, charset));
      rsp.end(body)
    })

exports.mwl = function(req, rsp, next){
  var ext = path.extname(req.url).replace(/^\./, '')
  req.originalExt = ext

  // This prevents the source files from being served, but also
  // has to factor in that in this brave new world, sometimes
  // `.html` (Handlebars, others), `.css` (PostCSS), and
  // `.js` (Browserify) are actually being used to specify
  // source files

  //if (['js'].indexOf(ext) === -1) {
    if (terraform.helpers.processors["html"].indexOf(ext) !== -1 || terraform.helpers.processors["css"].indexOf(ext) !== -1 || terraform.helpers.processors["js"].indexOf(ext) !== -1) {
      notFound(req, rsp, next)
    } else {
      next()
    }
  //} else {
    //next()
  //}
}

// not sure what this does anymore.
  if(!contents || contents.replace(/^\s\s*/, '').replace(/\s\s*$/, '') == ''){
    contents = '{}'
  }

  // attempt to parse the file
  try{
    var cfg = JSON.parse(contents)
  }catch(e){
    e.source    = "JSON"
    e.dest      = "CONFIG"
    e.message   = e.message
    e.filename  = configPath
    e.stack     = contents
    e.lineno    = -1
    throw new terraform.helpers.TerraformError(e)
  }

  if(!cfg.hasOwnProperty('globals')) cfg['globals'] = {}

  cfg.globals.environment = process.env.NODE_ENV || env

  // replace values that look like environment variables
  // e.g. '$foo' -> process.env.foo
  cfg = envy(cfg)

  return {
    projectPath : projectPath,
    publicPath  : publicPath,
    config      : cfg
  }

skin(req, rsp, [poly], function(){
    var priorityList  = terraform.helpers.buildPriorityList("200.html")
    var sourceFile    = terraform.helpers.findFirstFile(req.setup.publicPath, priorityList)
    if(!sourceFile) return next()

    req.poly.render(sourceFile, function(error, body){
      if(error){
        // TODO: make this better
        rsp.statusCode = 404;
        rsp.end("There is an error in your " + sourceFile + " file")
      }else{
        if(!body) return next()
        var type    = helpers.mimeType("html")
        var charset = mime.charsets.lookup(type)
        rsp.setHeader('Content-Type', type + (charset ? '; charset=' + charset : ''));
        rsp.setHeader('Content-Length', Buffer.byteLength(body, charset));
        rsp.statusCode = 200;
        rsp.end(body)

terra.render(file, function(error, body){
        if(error){
          done(error)
        }else{
          if(body){
            var dest = path.resolve(outputPath, terraform.helpers.outputPath(file))
            fs.mkdirp(path.dirname(dest), function(err){
              fs.writeFile(dest, body, done)
            })
          }else{
            if (file === "bundle.cjs"){

              var b = browserify({
                entries: [path.resolve(setup.publicPath, "bundle.cjs")],
                cache: {},
                packageCache: {},
                plugin: []
              })

              var dest   = path.resolve(outputPath, "bundle.js")
              var chunks = []
              var stream = b.bundle()