Node-dummy-cache NPM

node-dummy-cache

A simple in memory cache to use with javascript.

Installation

node.js

npm install node-dummy-cache

Import inside your code:

var cacheFactory = require('node-dummy-cache');

HTML

Download lib/dummy-cache.js.

Import inside HTML:

<script type="text/javascript" src="dummy-cache.js"></script>

For old browsers you will also need json2.js.

Usage

Simple key/value

var users = cacheFactory.create(cacheFactory.ONE_HOUR);

users.put(1, { name : 'A' });

var user = users.get(1);

Function style

Before:

function dummy(a, b, c, callback) {
	// Do complex stuff here
	callback(undefined, 'A', 'B');
};

dummy(1, 2, 3, function(err, data1, data2) {
	// You got it
});

Adding cache:

var dummy = cacheFactory.create(cacheFactory.ONE_HOUR, function (a, b, c, callback) {
	// Do complex stuff here
	callback(undefined, 'A', 'B');
});

dummy(1, 2, 3, function(err, data, data2) {
	// You got it
});

Promise style

Before:

function dummy(a, b, c) {
	return new Promise(function(resolve, reject) {
		// Do complex stuff here
		resolve('A');
	});
};

dummy(1, 2, 3).then(function(data) {
	// You got it
});

Adding cache:

var dummy = cacheFactory.create(cacheFactory.PROMISE, cacheFactory.ONE_HOUR, function (a, b, c) {
	return new Promise(function(resolve, reject) {
		// Do complex stuff here
		resolve('A');
	});
});

dummy(1, 2, 3).then(function(data) {
	// You got it
});

Fetch when needed (callback style)

var users = cacheFactory.create(cacheFactory.ONE_HOUR, function (id, callback) {
	// Do complex stuff here
	callback(undefined, user);
});

users.get(1, function(err, user) {
	// You got it
});

Fetch when needed (promise style)

var users = cacheFactory.create(cacheFactory.PROMISE, cacheFactory.ONE_HOUR, function (id) {
	return new Promise(function(resolve, reject) {
		// Do complex stuff here
		resolve(user);
	});
});

users.get(1).then(function(user) {
	// You got it
});

Mixed

var users = cacheFactory.create(cacheFactory.ONE_HOUR, function (id, callback) {
	// Do complex stuff here
	callback(undefined, user);
});

users(1, function(err, user) {
	// You got it
});

users.get(1, function(err, user) {
	// You got it
});

users.getAsPromise(1).then(function(user) {
	// You got it
});

var user = users.get(1); // Returns only if cached

user = users(1); // Returns only if cached

Complex

var users = cacheFactory.create(cacheFactory.ONE_HOUR, function (id1, id2, callback) {
	// Do complex stuff here
	callback(undefined, user, date);
});

users.get(1, 2, function(err, user, date) {
	// You got it
});

var user = users.get(1, 2); // Returns the user only if cached

users.put(1, 2, user); // Adds the user, but no date

API

All arguments passed to the get / put must be JSON serializable.

cacheFactory.create({ type: string, maxAliveTimeMS: number, maxNotAccessedTimeMs: number, onErrorMaxAliveTimeMs: number }, fetcher: function)

Creates a new cache.

This is the base constructor, all the other ones are shortcuts to this.

Params:

An object with the cache configuration. The available fields are: - type : one of cacheFactory.CALLBACK or cacheFactory.PROMISE. The default is CALLBACK. - maxAliveTimeMS : Max time a value will stay in cache starting with its creation. The default is forever. - maxNotAccessedTimeMs : Max time a value will stay in cache after its last access. The default is to only consider alive time. - onErrorMaxAliveTimeMs : Max time a value will stay in cache when an error is returned. The default is the same as maxAliveTimeMS.
fetcher : callback to fetch the data

cacheFactory.create(type: string, maxAliveTimeMS: number, maxNotAccessedTimeMs: number, fetcher: function)

Creates a new cache.

Params:

type : one of cacheFactory.CALLBACK or cacheFactory.PROMISE
maxAliveTimeMS : Max time a value will stay in cache starting with its creation
maxNotAccessedTimeMs : Max time a value will stay in cache after its last access
fetcher : callback to fetch the data

cacheFactory.create(maxAliveTimeMS: number, maxNotAccessedTimeMs: number, fetcher: function)

Creates a new cache. Fetcher expects a callback.

Params:

maxAliveTimeMS : Max time a value will stay in cache starting with its creation
maxNotAccessedTimeMs : Max time a value will stay in cache after its last access
fetcher : callback to fetch the data

cacheFactory.create(type: string, maxAliveTimeMS: number, fetcher: function)

Creates a new cache.

Params:

type : one of cacheFactory.CALLBACK or cacheFactory.PROMISE
maxAliveTimeMS : Max time a value will stay in cache starting with its creation
fetcher : callback to fetch the data

cacheFactory.create(maxAliveTimeMS: number, fetcher: function)

Creates a new cache. Fetcher expects a callback.

Params:

maxAliveTimeMS : Max time a value will stay in cache starting with its creation
fetcher : callback to fetch the data

cacheFactory.create(maxAliveTimeMS: number, maxNotAccessedTimeMs: number)

Creates a new cache. All values must be added to cache using put.

Params:

maxAliveTimeMS : Max time a value will stay in cache starting with its creation
maxNotAccessedTimeMs : Max time a value will stay in cache after its last access