old_contents: var File = require("./transformation/file");
  var util = require("./util");
  var each = require("lodash/collection/each");
  var t    = require("./types");
  
  module.exports = function (body, namespace, whitelist = []) {
    each(File.helpers, function (name) {
      if (whitelist.length && whitelist.indexOf(key) >= 0) return;
  
      var key = t.identifier(t.toIdentifier(name));
      body.push(t.expressionStatement(
        t.assignmentExpression("=", t.memberExpression(namespace, key), util.template(name))
      ));
    });
  };
  
new_contents: var File = require("./transformation/file");
  var util = require("./util");
  var each = require("lodash/collection/each");
  var t    = require("./types");
  
  module.exports = function (body, namespace, whitelist = []) {
    each(File.helpers, function (name) {
      if (whitelist.length && whitelist.indexOf(name) == -1) return;
  
      var key = t.identifier(t.toIdentifier(name));
      body.push(t.expressionStatement(
        t.assignmentExpression("=", t.memberExpression(namespace, key), util.template(name))
      ));
    });
  };
  
subject: fix helper whitelist in build script