isomorphic-relay-environment.js

import { Environment, Network, RecordSource, Store } from 'relay-runtime';
import RelayPublishQueue from 'relay-runtime/lib/store/RelayPublishQueue.js';
import RelayDefaultHandlerProvider from 'relay-runtime/lib/handlers/RelayDefaultHandlerProvider.js';

const network = Network.create(fetchQuery);
const createEnvironment = (records = {}) => {
	const source = new RecordSource(records);
	const store = new Store(source);

	return new Environment({
		network,
		store,
	});
};

let memoEnv = null;
export const getEnvironment = (records = {}) => {

	if (!process.browser) {
		if (memoEnv === null) {
			memoEnv = createEnvironment(records);
		} else {
			const source = new RecordSource(records);
			const store = new Store(source);
			memoEnv._store = store;
			memoEnv._publishQueue = new RelayPublishQueue(store, RelayDefaultHandlerProvider, memoEnv._getDataID);
		}
	} else if (memoEnv === null) {
		memoEnv = createEnvironment(records);
	}

	return memoEnv;
};