@nesvet/tasks

A small typed task registry built on EventEmitter: you define a glossary of Task subclasses, run them by name with Tasks.do, and listen for lifecycle events. Depends on eventemitter3 and @nesvet/n for helpers and typed errors.

Install

npm install @nesvet/tasks

Usage

import { Task, Tasks } from "@nesvet/tasks";

class EchoTask extends Task<string> {
	async do(message: string) {
		return message.toUpperCase();
	}
}

const tasks = Tasks.init({ echo: EchoTask });

tasks.on("echo.begin", (task) => {
	// …
});

const task = tasks.do("echo", "hello");
const result = await task.whenExecuted();

Subclass do receives the arguments you pass to tasks.do(name, …args).

API

Task<Result> — execute() runs do(...args) once; setState merges into state and emits state; abort sets error and calls optional onAbort; whenExecuted() returns the result promise. Fields: args, status (idle | executing | success | error), state (result, error, plus your keys). Events: executing, state, success, error.

Tasks<Glossary> — do(name, …args) starts a task (or returns the existing run if the same name and same args are already running); running is a Map of active instances; availableParallelism mirrors os.availableParallelism. Factory: Tasks.init(glossary, options?). Per-task events use the task key as a prefix, for example echo.begin, echo.end, echo.state, and echo.error; the registry also emits error for uncaught failures.

Options — verbose?: boolean logs each setState payload to the console.

License

MIT — repository.