Crude tracer

gistfile1.js

// Optionally log all calls done to prototype methods. Uncomment this
// section to get traces when trying to debug where flow gets stuck.
Object.keys(Email.prototype).forEach(function(key) {
  var desc = Object.getOwnPropertyDescriptor(Email.prototype, key);
  if (!desc.get && !desc.set && typeof Email.prototype[key] === 'function') {
    var oldMethod = Email.prototype[key];
    Email.prototype[key] = function() {

      var args = Array.prototype.slice.call(arguments, 0).map(function(arg) {
        return String(arg);
      }).join(', ');

      console.log('Email.' + key + '(' + args + ')');
      return oldMethod.apply(this, arguments);
    };
  }
});