actions.js

// utility functions for the authLogin
function authLoginStart(){
	return {
		type: AUTH_LOGIN_START
	};
}

function authLoginSuccess(user){
	return {
		type: AUTH_LOGIN_SUCCESS,
		user
	};
}

function authLoginError(errors){
	return {
		type: AUTH_LOGIN_ERROR,
		errors
	};
}

// actual auth login
function authLoginRest(data){
	return (dispatch) => {
		// starts the dispatching action
		dispatch(authLoginStart());
		// performs the login
		return login(data)
			.then(
				(user) => {
					dispatch(authLoginSuccess(user));
					dispatch(authSetToken(user.token));
					dispatch(authSetUser(user));
					return user;
				},
				(errors) => {
					dispatch(authLoginError(errors));
					return Promise.reject(errors);
				}
			);
	};
}

function authLoginSubmit(formName, data){
	return dispatch => {
		// start submitting the form
		dispatch(startSubmit(formName));
		// performs the actual login <=== COMPOSITION IS HERE
		return authLoginRest(data)(dispatch)
			.then(
				(user) => {
					dispatch(stopSubmit(formName));
					return user;
				},
				(errors) => {
					dispatch(stopSubmit(formName, errors));
					return Promise.reject(errors);
				}
			);
	};
}

I meant this instead:

function authLoginSubmit(formName, data){
    return dispatch => {
        dispatch(startSubmit(formName));
        return dispatch(authLoginRest(data)).then(
            (user) => {
                dispatch(stopSubmit(formName));
                return user;
            },
            (errors) => {
                dispatch(stopSubmit(formName, errors));
                return Promise.reject(errors);
            }
        );
    };
}