kiper

Keep objects available everywhere in nodejs application

How to use

First you need to install kiper using npm:

npm install kiper --save

Then, use kiper in your project:

const kiper = require('kiper');

// somewhere keep an asset
kiper.keep('foo', 'bar');

// somewhere you got it back
let value = kiper.get('foo');
console.log(value);

Main features

• Keep objects and cache them in memory
• Keep an object with a timeout (TTL - time to live)
• Observe key if its value has any changed
• Add/listen a custom event

Usecases

• Cache object
• Observing the changes to an object
• Send and receive messages through events
• Create agents and manage them. Such as: Chatbot manager, Dialog manager, ...
• Etc, ...

API Usage

Class: Kiper(options)

The Kiper class is defined and exposed by the module kiper
Added in: v0.0.1
Options:

• ttl: (default: 0) - time to live in milliseconds. 0 = infinity
• checkPeriod: (default: 600) - duration to check timeout on key has expired.
• checkUsage: (default: true) - check the last time usage

// create new instance of Kiper
const kiper = require('kiper').Kiper(options);

Method: .keep(key: string, value: object)

Keep an object in kiper
Added in: v0.0.1
Alias: set

kiper.keep('foo', 'bar');

Method: .keep(key: string, value: object, ttl: int, timeout: function)

Keep an object for a period of time
Added in: v0.1.0
Alias: set

kiper.keep('foo', 'bar', 1000, console.log);
// output: bar foor

Method: .get(key: string)

Get an object from kiper
Added in: v0.0.1

kiper.get('foo');
// returns: bar

Method: .get(validator: function)

Get an object from kiper by pass a validator function
Added in: v0.0.2

kiper.get((value, key) => value === 'bar');
// returns: bar

Method: .remove(key: string)

Remove an object out of kiper
Added in: v0.1.0

kiper.remove('foo');
// returns: bar

Method: .retire()

Stop interval checking, free memory and release objects
Added in: v0.1.0

kiper.retire();

Method: .touch(key)

Repair the last time usage
Added in: v1.0.0

kiper.touch('foo');

Method: .watch(key, callback)

Watch a key, if its value changes then a callback will be called
Added in: v1.0.0

// keep an asset and return an obserable object 
let baz = kiper.keep('baz', {
    gold: 1000
});

// watch the key
kiper.watch('baz', (obj, oldVal, propkey, type) => {
    console.log('change info:', obj, oldVal, propkey, type);
    // change info: { gold: 999 } 1000 gold update
    // change info: { silver: 1000 } undefined silver add
    // change info: {} 999 gold delete
});

// baz lost one gold
baz.gold = 999
// baz has new silvers
baz.silver = 1000
// baz lost all golds
delete baz.gold

Method: .on(event, listener)

Listen an event which emit from kiper
Added in: v1.0.0

kiper.keep('foo', 'bar', 1000);
kiper.on('expired', (value, key) => {
    console.log('A timeout on key has expired', value, key);
    // A timeout on key has expired bar foo
})

Method: .once(event, listener)

Listen an event once which emit from kiper
Added in: v1.0.0

kiper.keep('foo', 'bar', 1000);
kiper.once('expired', (value, key) => {
    console.log('A timeout on key has expired', value, key);
    // A timeout on key has expired bar foo
})

License

MIT