least-recent

library1.0.3jsnpmunverified

An LRU cache that evicts least-recently-used items when full. Current version 1.0.3, stable with low release cadence. Fork of Mnemonist's LRUCache with added eviction event emission via nanoevents. Differentiator: emits 'evicted' event on eviction, unlike Mnemonist. Pure ESM package, requires Node >=14 or modern browser.

database

npm install least-recent

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · LEAST-RECENT

least-recent

databasejavascriptv1.0.3

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.

LRUCache

✓ import { LRUCache } from 'least-recent'

✗ const LRUCache = require('least-recent')

ESM-only since v1.0.0; no CommonJS support.

LRUCache

✓ import { LRUCache } from 'least-recent'

✗ import LRUCache from 'least-recent'

Only named export, no default export.

Creates an LRU cache with capacity 3, adds entries, demonstrates get and eviction event listener.

import { LRUCache } from 'least-recent'; const cache = new LRUCache<string, number>(3); cache.set('a', 1); cache.set('b', 2); console.log(cache.get('a')); // 1 cache.set('c', 3); console.log(cache.get('b')); // 2 cache.set('d', 4); // 'c' was evicted console.log('size:', cache.size); // 3 cache.on('evicted', (key, value) => { console.log(`evicted: ${key}=${value}`); });

Debug

Known issues

breakingPackage is ESM-only; requires Node >=14 and "type": "module" in package.json.

fix

Ensure your project is ESM or use dynamic import() for CommonJS.

affects: >=1.0.0

deprecatedThe 'evicted' event may be removed in future major versions; prefer subclassing if event logic is critical.

fix

Monitor releases; consider forking if event behavior is essential.

affects: >=1.0.0

gotchaCapacity is required; no default. If omitted, cache does not evict and grows unbounded.

fix

Always pass a positive integer capacity.

affects: >=1.0.0

gotchaThe cache emits 'evicted' only on set() when capacity is exceeded, not on other methods like delete() or clear().

fix

Handle eviction only once per set() and not on explicit removal.

affects: >=1.0.0

gotchaMeant for in-memory caching in Node.js; may not work in older browsers without polyfills for Map and WeakMap.

fix

Use a transpiler/bundler that provides Map polyfill if targeting very old environments.

affects: >=1.0.0

Errors

Common errors & fixes

SyntaxError: Unexpected token 'export'

CommonJS require() of ESM package.

fix

Use import { LRUCache } from 'least-recent' instead of require.

Error [ERR_REQUIRE_ESM]: require() of ES Module

Running CommonJS script trying to require the package.

fix

Convert to ES module ("type": "module" in package.json) or use dynamic import()

TypeError: cache.on is not a function

Attempting to use 'on' method on an older version without eviction events or misunderstanding API.

fix

Ensure you installed version 1.0.0+ and are calling on('evicted', callback).

RangeError: Invalid capacity: must be a positive integer

Passing a non-positive or non-integer capacity to LRUCache constructor.

fix

Pass a positive integer (e.g., new LRUCache(1000)).

Upgrade

Version history

1.0.3latest on npm

Audit

Dependencies

nanoeventsrequiredEvent emitter for the 'evicted' event; pulled in automatically.

Agent activity

6 hits · last 30 days

node

Resources

githubhttps://github.com/ceramicnetwork/least-recent ↗

packageleast-recent ↗

homepagehttps://github.com/ceramicnetwork/least-recent ↗