Currying with generator

currying-with-generator.js

function *step(fn) {
  var arr = Array(fn.length);
  for (var i = 0; i < arr.length; i++) {
    arr[i] = (yield);
  }
 
  var gen = fn.apply(null, arr);
 
  return gen;
}
 
// Demo function
function timeout(a, b) {
  setTimeout(a, b);
  return "The end";
}
 
 
// Usage:
var res = step(timeout);
var out = res.next();
 
// arguments for timeout
var args = [console.log.bind(console, 1), 100];
while (!out.done) {
  // passing a and b to timeout
  out = res.next( args.shift() );
}

console.log(out.value); // -> "The end"