factorio-clusterio/packages/web_ui/src/model/instance.ts

import { useCallback, useContext, useEffect, useState, useSyncExternalStore } from "react";
import { Static } from "@sinclair/typebox";
import { Config, InstanceConfigGetRequest } from "@clusterio/lib";
import ControlContext from "../components/ControlContext";

export function useInstance(id?: number) {
	const [instances, synced, error] = useInstances();
	return [id !== undefined ? instances.get(id) : undefined, synced, error] as const;
}

export function useInstances() {
	const control = useContext(ControlContext);
	const subscribe = useCallback((callback: () => void) => control.instances.subscribe(callback), [control]);
	return useSyncExternalStore(subscribe, () => control.instances.getSnapshot());
}

export function useInstanceConfig(id?: number) {
	let control = useContext(ControlContext);
	const [config, setConfig] = useState(undefined as undefined | Static<typeof Config.jsonSchema>);

	useEffect(() => {
		setConfig(undefined);
		if (id === undefined) {
			return undefined;
		}

		// Responses for a previous id must not overwrite the current one.
		let current = true;
		control.send(new InstanceConfigGetRequest(id))
			.then(conf => { if (current) { setConfig(conf); } })
			.catch(() => {}); // Config is optional, the caller falls back to not having it
		return () => { current = false; };
	}, [id]);

	return config;
};