map-cache-ttl

library0.1.1jsnpmunverified

A Map subclass with TTL-based expiration for caching in Node.js (v0.1.1). It extends ES6 Map with optional per-key max age and automatic or manual trimming of expired entries. Supports proxy wrapping for memoization of async functions with cached results. Lightweight, no external dependencies required (except object-hash for proxy). Ideal for simple in-memory caching with fine-grained control over expiration.

storage

npm install map-cache-ttl

package ↗

INSTALL

IMPORT

SIG · MAP-CACHE-TTL

map-cache-ttl

storagejavascriptv0.1.1

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

✓ const Cache = require('map-cache-ttl')

✗ import Cache from 'map-cache-ttl' (default import not supported, use require or ESM with createRequire)

The package is CommonJS only. For ES modules, use createRequire.

constructor

✓ new Cache(maxAge, interval)

✗ new Cache({ maxAge: 5000, interval: 60000 }) (config object not supported)

Constructor takes two arguments: maxAge (number in ms) and interval (optional, number in ms for auto-trim).

proxy

✓ const proxy = cache.proxy(fn, maxAge)

✗ cache.proxy(fn, { maxAge: 5000 }) (options object not supported)

Second argument is optional per-proxy maxAge in ms.

Shows basic usage: creating a cache with 5s default TTL and 1s auto-trim, setting a key with 10s TTL, checking existence, and using proxy to memoize a fetch call for 30s.

const Cache = require('map-cache-ttl'); const cache = new Cache(5000, 1000); // default maxAge 5s, auto-trim every 1s cache.set('key', 'value', 10000); // expires in 10s console.log(cache.has('key')); // true setTimeout(() => console.log(cache.has('key')), 11000); // false after 11s const proxy = cache.proxy((url) => fetch(url).then(r => r.text()), 30000); proxy('https://example.com').then(data => console.log(data));

Debug

Known issues

gotchacache.size triggers cache.trim() internally, which may be O(n) and modifies internal state. Do not use size in performance-critical loops.

fix

Maintain your own counter or use cache.has(key) for specific keys.

affects: >=0.0.0

gotchaCalling cache.size or iterating after many insertions may not reflect accurate count if trim hasn't run; size forces trim.

fix

Use cache.trim() manually before reading size if you need precise counts without side effects.

affects: >=0.0.0

gotchaProxy function hashes arguments using object-hash; mutable objects will cause cache misses after mutation. Avoid mutable arguments.

fix

Serialize mutable arguments to stable strings before passing to proxy.

affects: >=0.0.0

gotchaExpired keys are not removed automatically unless trim() is called (or interval set). Memory leak if trim not called regularly.

fix

Always provide an interval in constructor or call trim() periodically.

affects: >=0.0.0

Errors

Common errors & fixes

Cannot find module 'map-cache-ttl'

Package not installed or import path incorrect in ESM context.

fix

npm install map-cache-ttl. For ESM, use const Cache = require('map-cache-ttl') via createRequire.

TypeError: cache.set is not a function

Using Cache as constructor without new (e.g., Cache('5s')). Extends Map, must be instantiated with new.

fix

Use 'new Cache(...)'.

Invalid max_age: must be a number

Passed string like '5s' instead of milliseconds. The library expects numeric milliseconds.

fix

Use numbers: new Cache(5000) for 5 seconds.

Upgrade

Version history

0.1.1latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

12 hits · last 30 days

node

Resources

packagemap-cache-ttl ↗