Just a quick example of a generator function, mostly borrowed from https://davidwalsh.name/async-generators

generator-example.js

// Just a quick example of a generator function,
// mostly borrowed from https://davidwalsh.name/async-generators

function request(param) {
  console.log("called request() with " + param);
  makeAsyncCall( param, function(response){
      it.next( response );
  } );
}

function makeAsyncCall(param,cb) {
  console.log("called makeAsyncCall()");
  setTimeout(function(){
    console.log("async thingy done!!!");
    cb(param);
  }, 3000);
}

function *main() {
  let result1 = yield request( "param 1" );
  let result2 = yield request( "param 2 plus " + result1 );
  console.log( "Value of final result: " + result2 );
}

let it = main();
it.next();