atomSubject.ts

Purpose

This module provides AtomSubject and createAtomSubject(), combining atom behavior with the ability to emit values and errors manually.

Overview

AtomSubject is useful in integration layers where an external event source needs to be represented as an Nrgy atom. Unlike a normal SourceAtom, it can switch between a value state and an error state.

Conceptual Architecture

The implementation is built from two layers:

1. An internal source atom stores State<T>, explicitly encoding either a value state or an error state.
2. The exported result is a computed atom that either returns the value or throws the stored error.

Methods destroy(), next(), and error() are attached on top of that computed atom to form the AtomSubject<T> API.

Public API Description

type AtomSubject<T>

• Extends DestroyableAtom<T>.
• Adds next(value) and error(error).

createAtomSubject<T>(initialValue, options?): AtomSubject<T>

• initialValue: initial subject value.
• options: standard atom options.
• Returns an atom that can emit values and errors manually.

Usage Examples

import { createAtomSubject, effect } from '@nrgyjs/core';

const subject = createAtomSubject(0);

const subscription = effect(subject, (value) => {
  console.log(value);
});

subject.next(1);
subject.error(new Error('boom'));
subscription.destroy();
subject.destroy();