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require()
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A simple in-memory cache for node.js. By Fabio Rotondo.
yarn add simple-mem-cache
or
npm install simple-mem-cache --save
var smc = require ( 'simple-mem-cache' );
// now just use the cache
smc.add ( 'hello', 'world' );
// add an item that expires after 6 seconds
smc.add ( 'expiring', 'in 6 seconds', 6000 );
// add an item that when expires calls a cback
smc.add ( 'boom', 'exploding', 3000, ( key, val ) => {
console.log ( 'KA-BOOOM for k: %s - v: %s', key, val );
} );
// Get values
console.log ( 'Hello: ', smc.get ( 'hello' ) );
console.log ( 'expiring: ', smc.get ( 'expiring' ) );
console.log ( 'boom: ', smc.get ( 'boom' ) );
which should print
Hello: world
expiring: in 6 seconds
boom: exploding
and after 6 seconds, also:
KA-BOOOM for k: boom - v: exploding
You can obtain the full items collection with:
// Get current items as JSON string
const s = smc.stringify ();
And also add elements to the cache by parsing a previously JSON dump:
// Adding elements from a previously JSON dump
smc.parse ( s );
With the skipExisting flag, you will not override elements in the memory cache:
// Adding elements from a previously JSON dump skipping keys already present
smc.parse ( s, true );
Stores a value in the cache. You can automatically remove the given value from the cache providing the expire attribute (a numeric value indicating the duration time of the value expressed in milliseconds). Also, optionally, if the value is going to expire, you can specify an expireation callback to be called at that time.
key: the cache key name for retrieving value
value: the cache value. Can be any JavaScript type.
expire: the value duration time in memory (in milliseconds). If omitted, the key will last forever.
expireCallback: the callback to be called when the item expires from cache. It will be called with the following signature:
expireCallback ( key, value )
This method returns the value just cached.
Retrieves the value for the specified key. If the key is not found in the cache, defaultValue is returned.
This method returns the value in cache or defaultValue.
Deletes the provided key from the cache.
This method returns nothing.
Completely swipe cache data from memory.
This method returns nothing.
Returns a string rappresentation of key/values in memory.
Returns a JSON string rappresenting the current key/values in memory.
Restore keys / values inside the json string into memory cache. If skipExisting is true, keys already present in the memory cache are preserved.
Returns all the keys currently in cache.
This is a class read only property that returns the numeber of keys in the cache.
This is a class read only property that returns the number of cache hits.
This is a class read only property that returns the number of cache misses.
0.1.3: Added jest tests