LRU cache module written in C++
npm install lru-native2lru-native2
===========
This is an implementation of a simple in-memory cache for node.js, supporting LRU (least-recently-used) eviction
and TTL expirations.
It was developed as an alternative to the (excellent) node-lru-cache
library for use with hashes with a very large number of items. V8 normally does a good job of optimizing the
in-memory representation of objects, but it isn't optimized for an object that holds a huge amount of data.
When you add a very large number of properties (particularly with non-integer keys) to an object, performance
begins to suffer.
Rather than rely on V8 to figure out what we're trying to do, node-lru-native is a light wrapper aroundstd::unordered_map from C++11. A std::list is used to track accesses so we can evict the least-recently-used
item when necessary.
Based on the node-hashtable library by Issac Wagner.
Install via npm:
``
$ npm install lru-native2
Then:
`javascript`
var LRUCache = require('lru-native2');
var cache = new LRUCache({ maxElements: 1000 });
cache.set('some-key', 42);
var value = cache.get('some-key');
If you'd like to tinker, you can build the extension using node-gyp:
`
$ npm install -g node-gyp
$ node-gyp configure
$ node-gyp build
To configure the cache, you can pass a hash to the LRUCache constructor with the following options:
`
var cache = new LRUCache({
// The maximum number of items to add to the cache before evicting the least-recently-used item.
// Default: 0, meaning there is no maximum.
maxElements: 10000,
// The maximum age (in milliseconds) of an item.
// The item will be removed if get() is called and the item is too old.
// Default: 0, meaning items will never expire.
maxAge: 60000,
// The initial number of items for which space should be allocated.
// The cache will resize dynamically if necessary.
size: 1000,
// The maximum load factor for buckets in the unordered_map.
// Typically you won't need to change this.
maxLoadFactor: 2.0
});
`
Adds the specified item to the cache with the specified key.
Returns the item with the specified key, or undefined` if no item exists with that key.
Removes the item with the specified key if it exists.
Removes all items from the cache.
Returns the number of items in the cache.
Returns a hash containing internal information about the cache.
Set the maximum number of items
Set the maximum age (in milliseconds) of an item
- 1.2.x -- Support OSX, node 14/16
- 1.0.0 -- Update the timestamp when get a value(like common LRU cache). Added SetMaxAge(), SetMaxElements()
- forked
- 0.4.0 -- Added support for newer versions of Node via NAN
- 0.3.0 -- Changed memory allocation strategy, fixed issue where remove() would do a seek through the LRU list, code cleanup
- 0.2.0 -- Fixed issue where maxAge-based removal would result in a seek through the LRU list
- 0.1.0 -- Initial release