alscontext

library0.0.3jsnpmunverified

ALSContext is a Node.js library providing continuation-local storage (CLS) using AsyncLocalStorage with a fallback to a modified cls-hooked for older Node versions (8.12.0+). Current stable version 0.0.3 uses Node's built-in AsyncLocalStorage when available (>=12.17.0 or >=13.10.0) and a polyfill for older versions. It offers a consistent API for context propagation across async callbacks, with flat key-value operations and support for nested contexts. Unlike cls-hooked, nested run() calls create independent child contexts. It includes both a default ALS class (auto-detect) and a CLS class (force polyfill). TypeScript definitions are included and the package is ESM-first but supports CommonJS via named exports.

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npm install alscontext

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INSTALL

IMPORT

SIG · ALSCONTEXT

alscontext

devopsjavascriptv0.0.3

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.

ALS

✓ import ALS from 'alscontext'

✗ const ALS = require('alscontext')

Default export in ESM; CommonJS requires .default or named import

ALS

✓ const { ALS } = require('alscontext')

✗ const ALS = require('alscontext').default

Named export for CommonJS; .default also works

CLS

✓ import { CLS } from 'alscontext'

✗ import CLS from 'alscontext'

CLS is a named export, not default; forces use of the polyfill

Shows ALS usage as Express middleware: creating context, setting and getting values, and retrieving the store.

import ALS from 'alscontext'; import express from 'express'; const als = new ALS(); const app = express(); const port = 3000; app.use((req, res, next) => { als.run({ user: 'John Doe' }, () => { next(); }); }); app.use((req, res, next) => { const user = als.get('user'); // 'John Doe' als.set('user', 'Max'); next(); }); app.get('/', (req, res) => { res.json({ store: Array.from(als.getStore().entries()) }); }); app.listen(port, () => { console.log(`Running on http://localhost:${port}/`); });

Debug

Known issues

breakingCommonJS require('alscontext') returns the module exports, not the ALS class; you need .default or use destructuring.

fix

Use const { ALS } = require('alscontext') or const ALS = require('alscontext').default

affects: <1.0.0

gotchaNested run() creates a new child context; keys set in the parent are not visible in child unless passed via the initial object.

fix

Explicitly pass parent values to child run() if needed, e.g., als.run({ ...als.getStore(), key: value }, callback)

affects: >=0.0.0

gotchagetStore() returns a Map, not a plain object; iterate with .entries() or convert with Object.fromEntries()

fix

Use als.getStore().get('key') or Array.from(als.getStore().entries()) for serialization

affects: >=0.0.0

deprecatedUsing .default export via require is deprecated in favor of named exports.

fix

Use named export: const { ALS } = require('alscontext')

affects: >=0.0.0

Errors

Common errors & fixes

TypeError: ALS is not a constructor

Importing default export incorrectly in CommonJS: const ALS = require('alscontext')

fix

Use const ALS = require('alscontext').default or const { ALS } = require('alscontext')

TypeError: als.run is not a function

Importing CLS as default export instead of named export

fix

Import CLS as named export: const { CLS } = require('alscontext') or import { CLS } from 'alscontext'

TypeError: als.getStore is not a function

Using an older version or incorrect instantiation of ALS/CLS

fix

Ensure you are using version 0.0.3 and follow the correct import (see above)

Upgrade

Version history

0.0.3latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

27 hits · last 30 days

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OpenAI (training)

Resources

githubhttps://github.com/Darkripper214/ALS-Context ↗

packagealscontext ↗

homepagehttps://github.com/Darkripper214/ALS-Context#readme ↗