async-functions.sjs

macro function! {
  case { $macro $name ($params ...) { $body ...} } => {
    letstx $await = [makeIdent("await", #{$macro})];
    return #{
      function $name($params ...) {
        return spawn(gen($params ...));
      }

      function* gen($params ...) {
        let $await = macro {
          case { _ $[$rest ...] } => {
            return #{yield $[$rest ...]}
          }
        }
        $body ...
      }
    }
  }
}

function spawn(gen) {
  function _next(v) { return handle(gen.next(v)); }
  function _throw(e) { return handle(gen.throw(e)); }

  function handle(result) {
    var value = result.value;
    if (!result.done && value && typeof value.then === "function") {
      return value.then(_next, _throw);
    }
    return value;
  }

  return new Promise(function(resolve, reject) {
    Promise.cast(_next()).then(resolve, reject);
  });
}


function! test(array) {
  array = await promiseMap(array, getAsync);
  return promiseMap(array, getNameAync);
}

spawn.js

// See http://taskjs.org for the original.
function spawn(thunk) {
  var gen;

  function _next(v) { return handle(gen.next(v)); }
  function _throw(e) { return handle(gen.throw(e)); }

  function handle(result) {
    var value = result.value;
    if (!result.done && value && typeof value.then === "function") {
      return value.then(_next, _throw);
    }
    return value;
  }

  return new Promise(function(resolve, reject) {
    gen = thunk();
    Promise.cast(_next()).then(resolve, reject);
  });
}