Cache

A simple, efficient caching module for Node.js applications.

It handles maxAge (aka ttl) and the storage location and file names can be configured

See MaxAge and Config

Installation

Install the package via npm:

npm install @ricb/cache

Usage

Store and retrieve

import { put, get } from '@ricb/cache';

const key = 'testKey';
const value = 'testValue';

await put(key, value);
const result = await get(key);
console.log(result); // Outputs: 'testValue'

Retrieve with max age

import { put, get } from '@ricb/cache';

const key = 'testKey';
const value = 'testValue';

await put(key, value);
await new Promise(resolve => setTimeout(resolve, 11));
const result = await get(key, '10 ms');
console.log(result); // Outputs: null

MaxAge

MaxAgeParam is a type that can be a string, number, or MaxAgeObject. It is used to specify the maximum age for a cache entry.

MaxAgeObject

MaxAgeObject is an object that can have the following properties:

• d or days: The number of days.
• h or hours: The number of hours.
• m or minutes: The number of minutes.
• s or seconds: The number of seconds.
• ms or milliseconds: The number of milliseconds.

Each property is optional and can be used to specify the maximum age in different units of time.

maxAgeToMs Function

The maxAgeToMs function is used to convert a MaxAgeParam to milliseconds. It accepts a MaxAgeParam as an argument and returns a number.

If the MaxAgeParam is a number, it is returned as is. If it is a string, it is parsed and converted to milliseconds. If it is a MaxAgeObject, each property is converted to milliseconds and summed up.

Here are some examples of how to use maxAgeToMs:

// Using a number
const maxAgeMs1 = maxAgeToMs(1000);
console.log(maxAgeMs1); // Outputs: 1000

// Using a string
const maxAgeMs2 = maxAgeToMs('2 hours');
console.log(maxAgeMs2); // Outputs: 7200000

// Using a MaxAgeObject
const maxAgeMs3 = maxAgeToMs({ days: 3 });
console.log(maxAgeMs3); // Outputs: 259200000

Config

The cache module allows you to configure the cache directory and prefix using the config function or setCacheDir and setPrefix functions.

init Function

The config function is used to initialize the cache directory and prefix. It accepts two optional arguments:

• prefix: The prefix to be used for the cache files.
• cacheDir: The directory where the cache files will be stored.

If these arguments are not provided, the function will use the CACHE_DIR and CACHE_PREFIX environment variables. If these environment variables are also not set, it will use the system's temporary directory for cacheDir and an empty string for prefix.

setCacheDir Function

The setCacheDir function is used to set the cache directory. It accepts one argument:

• dir: The directory where the cache files will be stored.

setPrefix Function

The setPrefix function is used to set the prefix for the cache files. It accepts one argument:

• p: The prefix to be used for the cache files.

Here are some examples of how to use these functions:

// Initialize with a prefix and cache directory
init('_test.', __dirname);

// or set them individually
setCacheDir(__dirname);
setPrefix('_test.');