thunky

library1.1.0jsnpmunverified

Delay the evaluation of a paramless async function and cache the result. Version 1.1.0 is stable with no active development. It provides a simple thunk pattern for lazy initialization, caching the result after the first successful invocation. Supports both callback and Promise (via `thunky/promise`) styles. Lightweight with zero dependencies. Differentiators: minimal API, error handling that prevents caching on failure, and compatibility with Node.js and browsers via bundlers.

development

npm install thunky

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · THUNKY

thunky

developmentjavascriptv1.1.0

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.

thunky

✓ import thunky from 'thunky'

✗ const thunky = require('thunky')

ESM import (default export) works in Node.js >=12 with ESM support. For CJS, use require, but ESM is preferred.

thunky (promise)

✓ import thunkyp from 'thunky/promise'

✗ const thunkyp = require('thunky/promise')

Promise variant for async/await. Must use separate subpath import.

thunky (require CJS)

✓ const thunky = require('thunky')

✗ const { thunky } = require('thunky')

thunky is a default export, not named. Destructuring will give undefined.

Demonstrates both callback-based thunky and promise-based thunkyp, showing lazy evaluation and caching.

import thunky from 'thunky'; import thunkyp from 'thunky/promise'; const lazy = thunky((cb) => { setTimeout(() => cb('result'), 100); }); lazy((val) => console.log('callback:', val)); const lazyP = thunkyp(async () => { await new Promise(r => setTimeout(r, 100)); return 'promise result'; }); console.log('await:', await lazyP());

Debug

Known issues

deprecatedThe callback-based thunky is deprecated in favor of the Promise version.

fix

Migrate to thunky/promise and async/await for new code.

affects: >=1.1.0

breakingthunky/promise subpath is only available in version 1.1.0+

fix

Update to thunky@1.1.0 or later.

affects: <1.1.0

gotchaIf the thunk callback is called with an Error, the result is NOT cached, causing the inner function to be called again on next invocation.

fix

Ensure your async function does not call the callback with an Error for caching to work.

affects: >=1.0.0

Errors

Common errors & fixes

TypeError: thunky(...) is not a function

Using destructuring to import thunky as a named export (e.g., import { thunky } from 'thunky')

fix

Use default import: import thunky from 'thunky'

Error: Cannot find module 'thunky/promise'

Installed thunky version <1.1.0 or missing file

fix

Run npm install thunky@1.1.0

Upgrade

Version history

1.1.0latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

52 hits · last 30 days

node

Resources

githubgit://github.com/mafintosh/thunky ↗

packagethunky ↗

homepagehttps://github.com/mafintosh/thunky#readme ↗