example.js

// (This is psuedo code)

class fooAction extends store {
  addFoo(foo, bar, baz) {
    return new Promise(function(reject, resolve) {
      ajax(function(response, error) {
        if (error) {
          // I want to pass two arguments here but it will noly pass the first one.
          reject({foo, error});
        } else {
          resolve(response);
        }
      })
    });
  };  
}

class fooStore extends action {
  constructor() {
    super();
    let myActionIds = this.getActionId('foos');
    this.registerAsync(myActionIds.addFoo, this.handleFetching, this.handleSuccess, this.handleFail);
  }

  // "receives same arguments that were passed to the action."
  handleFetching(args) {
    // I expected my args to be foo, bar, baz but it's actually:
    // [actionArgs, actionId, async, dispatchId]
    let foo = args.actionArgs.foo;
    let bar = args.actionArgs.bar;
    let baz = args.actionArgs.baz;
  }

  // "receives the rejected value of the promise returned by the action (by
  // convention, an error object)."
  handleFail(args) {
    // It only passed the first argument, it would be nice to have all of them
    // and not have to unpack them
    let foo = args.foo;
    let error = args.error;
  }

  // "receives the resolved value of the promise returned by the action."
  handleSuccess(response) {
    // that was simple. first arg is the response
  }
}