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memory-cache Build Status

A simple in-memory cache for node.js

Installation

npm install memory-cache --save

Usage

var cache = require('memory-cache');

// now just use the cache

cache.put('foo', 'bar');
console.log(cache.get('foo'));

// that wasn't too interesting, here's the good part

cache.put('houdini', 'disappear', 100, function(key, value) {
    console.log(key + ' did ' + value);
}); // Time in ms

console.log('Houdini will now ' + cache.get('houdini'));

setTimeout(function() {
    console.log('Houdini is ' + cache.get('houdini'));
}, 200);


// create new cache instance
var newCache = new cache.Cache();

newCache.put('foo', 'newbaz');

setTimeout(function() {
  console.log('foo in old cache is ' + cache.get('foo'));
  console.log('foo in new cache is ' + newCache.get('foo'));
}, 200);

which should print

bar
Houdini will now disappear
houdini did disappear
Houdini is null
foo in old cache is baz
foo in new cache is newbaz

API

put = function(key, value, time, timeoutCallback)

  • Simply stores a value
  • If time isn't passed in, it is stored forever
  • Will actually remove the value in the specified time in ms (via setTimeout)
  • timeoutCallback is optional function fired after entry has expired with key and value passed (function(key, value) {})
  • Returns the cached value

get = function(key)

  • Retrieves a value for a given key
  • If value isn't cached, returns null

del = function(key)

  • Deletes a key, returns a boolean specifying whether or not the key was deleted

clear = function()

  • Deletes all keys

size = function()

  • Returns the current number of entries in the cache

memsize = function()

  • Returns the number of entries taking up space in the cache
  • Will usually == size() unless a setTimeout removal went wrong

debug = function(bool)

  • Turns on or off debugging

hits = function()

  • Returns the number of cache hits (only monitored in debug mode)

misses = function()

  • Returns the number of cache misses (only monitored in debug mode)

keys = function()

  • Returns all the cache keys

exportJson = function()

  • Returns a JSON string representing all the cache data
  • Any timeoutCallbacks will be ignored

importJson = function(json: string, options: { skipDuplicates: boolean })

  • Merges all the data from a previous call to export into the cache
  • Any existing entries before an import will remain in the cache
  • Any duplicate keys will be overwritten, unless skipDuplicates is true
  • Any entries that would have expired since being exported will expire upon being imported (but their callbacks will not be invoked)
  • Available options:
    • skipDuplicates: If true, any duplicate keys will be ignored when importing them. Defaults to false.
  • Returns the new size of the cache

Cache = function()

  • Cache constructor
  • note that require('cache') would return the default instance of Cache
  • while require('cache').Cache is the actual class

Note on Patches/Pull Requests

  • Fork the project.
  • Make your feature addition or bug fix.
  • Send me a pull request.