futoin-asyncsteps

library2.5.6jsnpmunverified

FutoIn AsyncSteps mimics traditional threads of execution in a single-threaded event loop, supporting cancellation, exit handlers, thread-local storage, and synchronization primitives like mutexes and throttles. Current stable version is 2.5.6, released under a stable maturity (status 3). It builds on the FTN12: FutoIn Async API v1.13 specification. Key differentiators include explicit step-based control flow (add, parallel, error handling) rather than Promises or async/await, though it integrates with Promises via as.await(). It is designed for both Node.js (>=8) and browser environments, providing ES5 CJS modules under es5/ and pre-built webpack dists under dist/. Synchronization primitives like Mutex are available for coordinated concurrent execution.

workflow

npm install futoin-asyncsteps

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · FUTOIN-ASYNCSTEPS

futoin-asyncsteps

workflowjavascriptv2.5.6

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

$as

✓ import $as from 'futoin-asyncsteps'

✗ const $as = require('futoin-asyncsteps').default

Default export is a factory function returning AsyncSteps instance. In CommonJS, use require('futoin-asyncsteps') directly.

AsyncSteps

✓ import { AsyncSteps } from 'futoin-asyncsteps'

✗ import AsyncSteps from 'futoin-asyncsteps'

AsyncSteps is a named export, not default. In CommonJS: const { AsyncSteps } = require('futoin-asyncsteps').

Mutex

✓ import { Mutex } from 'futoin-asyncsteps'

✗ const Mutex = require('futoin-asyncsteps').Mutex

Mutex is a named export. In browser, it may require WeakMap polyfill.

$as (browser)

✓ <script src='dist/futoin-asyncsteps.min.js'></script>... $as(...)

✗ import $as from 'futoin-asyncsteps' in non-module script

In browser, $as is a global; no import needed. Use script tag loading the dist.

Shows basic step execution chain with add() and success().

const $as = require('futoin-asyncsteps'); const root = $as(); root.add((as) => { console.log('Step 1'); as.success('done'); }).add((as, result) => { console.log('Step 2 received:', result); as.success(); }); root.execute();

Debug

Known issues

gotchaCalling as.success() more than once or after as.error() in a step causes undefined behavior.

fix

Ensure exactly one call to as.success() or as.error() per step (or none for implicit success).

affects: >=2.0

gotchaSynchronization primitives (Mutex, Throttle) require WeakMap polyfill in older browsers.

fix

Include dist/polyfill-asyncsteps.js before using Sync primitives in legacy browsers.

affects: >=2.0

gotchaThe as.state object is shared among all steps in the same AsyncSteps instance; mutations persist across steps.

fix

Use as.state for cross-step data, but be aware of unintended sharing when passing AsyncSteps instances or creating nested scopes.

affects: >=2.0

gotchaUsing as.await() with a rejected Promise will trigger error handling in the AsyncSteps flow, not throw an unhandled rejection.

fix

Ensure error handling steps are added after as.await() to catch rejections.

affects: >=2.0

gotchaParallel step results are not automatically merged; you must store results in as.state manually inside each parallel branch.

fix

Assign to as.state inside each parallel add() callback to collect outputs.

affects: >=2.0

Errors

Common errors & fixes

TypeError: $as is not a function

Imported default incorrectly (e.g., import { $as } instead of import $as).

fix

Use `import $as from 'futoin-asyncsteps'` or `const $as = require('futoin-asyncsteps')`.

Cannot find module 'futoin-asyncsteps'

Package not installed or wrong path in require/import.

fix

Run `npm install futoin-asyncsteps` and ensure import path is correct.

as.success is not a function

Calling as.success outside of a step callback (e.g., in the root scope or after step ends).

fix

Only call as.success() inside a step function passed to add(), parallel().add(), etc.

Upgrade

Version history

2.5.6latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

12 hits · last 30 days

node

Amazon

OpenAI (training)

Resources

githubhttps://github.com/futoin/core-js-ri-asyncsteps ↗

packagehttps://www.npmjs.com/package/futoin-asyncsteps ↗

homepagehttps://asyncsteps.futoin.org ↗