fetchUser method from React.js web app

fetchUser.js

export function fetchUser(__userIdNum, __authTokenStr) {

	return function (dispatch) {
		dispatch(requestUser(__userIdNum));

		const __url = `${BASE_URL}/api/user?id=${__userIdNum}`;
		let __headers = new Headers();
		__headers.append("Content-Type", 'application/json');
		__headers.append("X-API-Auth-Token", __authTokenStr);

		let __init = {
			method: 'GET',
			headers: __headers,
		}

		return fetch(__url, __init)
			.then(
				response => response.json(),
				error => console.log('An error occured.', error)
			)
			.then(json =>
				dispatch(receiveUser(__userIdNum, json))
			)
	}
}