tmp-cache

library1.1.0jsnpmunverified

A minimal least-recently-used (LRU) cache implementation in about 35 lines of code, extending the native Map class. At version 1.1.0 (latest), it supports configurable max size, per-item or global maxAge for expiration, and a stale option to return expired values before deletion. Released steadily since 2017, it has zero dependencies and ships TypeScript type declarations. Compared to heavier alternatives like lru-cache, tmp-cache prioritizes simplicity and small bundle size, making it suitable for lightweight caching in Node.js (>=6) or modern browsers.

storage

npm install tmp-cache

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · TMP-CACHE

tmp-cache

storagejavascriptv1.1.0

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.

Cache (default)

✓ import Cache from 'tmp-cache'

✗ const Cache = require('tmp-cache').default

ESM default export; CommonJS require returns the constructor directly, so require('tmp-cache') works without .default.

Cache (CommonJS)

✓ const Cache = require('tmp-cache')

✗ const { Cache } = require('tmp-cache')

CommonJS usage via require; the module exports a single class, not a named export.

Cache (TypeScript type)

✓ import type { Cache } from 'tmp-cache'

For TypeScript, you can import the class as a value or use type-only import for type annotations.

Basic LRU cache creation with max size, get, set, size, has, and expiration with stale mode.

import Cache from 'tmp-cache'; // Cache with max 3 items const cache = new Cache(3); cache.set('a', 1); cache.set('b', 2); cache.set('c', 3); cache.get('a'); // refreshes expiry, moves to end cache.set('d', 4); // evicts oldest (b) console.log(cache.has('b')); // false console.log(cache.size); // 3 // With maxAge (10ms) and stale allowed const ageCache = new Cache({ maxAge: 10, stale: true }); ageCache.set('foo', 'bar', 20); // custom maxAge setTimeout(() => { console.log(ageCache.get('foo')); // 'bar' (stale, then removed) console.log(ageCache.get('foo')); // undefined }, 15);

Debug

Known issues

gotchaThe options parameter can be an object or an integer. Passing an integer is treated as `max`.

fix

To set other options like maxAge, always pass an object: `new Cache({ max: 5, maxAge: 1000 })`.

affects: >=1.0.0

gotchaThe `get` method by default refreshes the item's expiration (resets maxAge timer). Use the `mutate` option to prevent refresh.

fix

Call `cache.get(key, false)` to retrieve without refreshing expiry.

affects: >=1.0.0

gotchaExpired items are not proactively purged; they are only removed on access or when evicted by max size.

fix

Do not rely on the cache to free memory automatically; call `delete` or `clear` explicitly if needed.

affects: >=1.0.0

gotchaThe `set` method accepts an optional third argument `maxAge` that overrides the instance's maxAge for that item.

fix

Pass `undefined` or omit the third argument to use the default maxAge.

affects: >=1.0.0

deprecatedThe package does not have deprecated features per se, but the API is stable and unlikely to change.

fix

No action needed.

affects: 1.1.0

Errors

Common errors & fixes

TypeError: Class extends value #<Object> is not a constructor or null

Using ES module import with CommonJS-required style or bundler misconfiguration.

fix

Use `import Cache from 'tmp-cache'` for ES modules, or `const Cache = require('tmp-cache')` for CommonJS.

Cannot find module 'tmp-cache' or its corresponding type declarations.

Package not installed or TypeScript cannot resolve types.

fix

Run `npm install tmp-cache` and ensure tsconfig.json includes `"moduleResolution": "node"`.

tmp-cache: `maxAge` must be a number

Passing a non-number (e.g., string) as maxAge to `set` or in options.

fix

Ensure maxAge is a number (milliseconds) or undefined. Example: `cache.set('key', value, 1000)`.

Upgrade

Version history

1.1.0latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

22 hits · last 30 days

node

Resources

githubhttps://github.com/lukeed/tmp-cache ↗

packagetmp-cache ↗

homepagehttps://github.com/lukeed/tmp-cache#readme ↗