Async Cancellables / AsyncState

Asynchronous class to track presence or absence of a value with builtin support of cancellation tokens

Table of contents

• Prerequisites
• Table of contents
• Installation
• API
  • Creating state
  • Waiting for a value
  • Accessing current value
• Authors
• License

Prerequisites

This project requires NodeJS (version 18 or later) and NPM.

Installation

To install and set up the library, run:

$ npm install @async-cancellables/async-state

API

Creating state

There are 2 types of AsyncState:

• manual state can be set only manually
• event state sets value after specified event on target object is fired, state value is set to the result of handler call with event arguments

import { AsyncState } from 'async-cancellables';

const manualState = AsyncState.manual(value = undefined);
const eventState = AsyncState.event(target, event, handler);

Waiting for the value

• wait(cancellationToken = null) waits for the value to be set to any defined value or returns it if already is
• waitEmpty(cancellationToken = null) waits for the value to be cleared back to undefined
• handleValue(handler, cancellationToken = null) waits for the value to be set to any defined value if not yet and returns the result of handler(value)

Accessing current value

• value simple property to access currently set value

Authors

• vuwuv - Initial work - vuwuv

License

[MIT License] © vuwuv