one/dist/esm/background/useBackgroundComputation.native.js

One is a React framework for web, iOS, and Android apps.

import { useCallback, useLayoutEffect, useRef, useState } from "react";
import { createLatestComputation } from "./createLatestComputation.native.js";

function useBackgroundComputation(definition, input) {
	var _submitted_current, _owner_current;
	var [state, setState] = useState({
		phase: "idle",
		revision: 0
	});
	var owner = useRef(null);
	var submitted = useRef(null);
	var active = input !== null;
	useLayoutEffect(function() {
		if (!active) return;
		var computation = createLatestComputation(definition, function(changed) {
			setState(changed.phase === "ready" ? {
				phase: "ready",
				revision: changed.result.revision
			} : changed);
		});
		owner.current = computation;
		return function() {
			owner.current = null;
			submitted.current = null;
			computation.dispose();
		};
	}, [active, definition]);
	useLayoutEffect(function() {
		var _owner_current2;
		if (input === null) return;
		submitted.current = {
			input,
			factory: definition
		};
		(_owner_current2 = owner.current) === null || _owner_current2 === void 0 ? void 0 : _owner_current2.update(input);
	}, [
		active,
		definition,
		input
	]);
	var getCurrent = useCallback(function() {
		var _ref;
		var _owner_current2;
		return (_ref = (_owner_current2 = owner.current) === null || _owner_current2 === void 0 ? void 0 : _owner_current2.getCurrent()) !== null && _ref !== void 0 ? _ref : null;
	}, []);
	var matches = active && ((_submitted_current = submitted.current) === null || _submitted_current === void 0 ? void 0 : _submitted_current.input) === input && submitted.current.factory === definition;
	if (matches && state.phase === "failed") throw state.error;
	var current = (_owner_current = owner.current) === null || _owner_current === void 0 ? void 0 : _owner_current.getCurrent();
	var result = matches && state.phase === "ready" && current && state.revision === current.revision ? current : null;
	return {
		result,
		getCurrent
	};
}

export { useBackgroundComputation };
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