generator-function 
A function that returns the normally hidden GeneratorFunction constructor, when available.
Getting started
npm install --save generator-function
Usage/Examples
const assert = require('assert');
const GeneratorFunction = require('generator-function')();
const fn = new GeneratorFunction('return 1');
assert.equal(fn.toString(), 'function* anonymous(\n) {\nreturn 1\n}');
const iterator = fn();
assert.deepEqual(iterator.next(), { done: true, value: 1 });
Tests
Clone the repo, npm install, and run npm test