zb-promise-cache

A cache object that can cache result of a promise for certain period of time

Simple usage

const PromiseCache = require('zb-promise-cache');


const simplePromise = function() {
  return new Promise((resolve, reject) => {
    resolve('hello world');
  });
}

const promiseCache = new PromiseCache(simplePromise);

p.get('testing')
  .then(function(val) {
    console.log(val); // 'hello world'

    // At this point 'hello world' is already cached
    // into 'promiseCache' object. Next time you call
    // p.get('testing'), the value will be retrieved
    // from cache.
  });

Advanced usage

const PromiseCache = require('zb-promise-cache');


const advancedPromise = function(someValue) {
  return new Promise((resolve, reject) => {
    resolve('hello world ' + someValue);
  });
}

const promiseCache = new PromiseCache(advancedPromise);

p.get('advanced testing', [1])
  .then(function(val) {
    console.log(val); // 'hello world 1'

    // At this point 'hello world 1' is already cached
    // into 'promiseCache' object with key 'advanced testing'. Next time you call
    // p.get('advanced testing', '2'), the value will be retrieved from cache
    // and will resolve 'hello world 1' in stead of 'hello world 2' unless cache expired.
  });

const PromiseCache = require('zb-promise-cache');


const advancedPromise = function(someValue, anotherValue) {
  return new Promise((resolve, reject) => {
    const sum = someValue + anotherValue;
    resolve('hello world ' + sum);
  });
}

const promiseCache = new PromiseCache(advancedPromise);

p.get('advanced testing', [2, 3])
  .then(function(val) {
    console.log(val); // 'hello world 5'

    // At this point 'hello world 5' is already cached
    // into 'promiseCache' object with key 'advanced testing'. Next time you call
    // p.get('advanced testing', [1111, 2222]), the value will be retrieved from cache
    // and will resolve 'hello world 5' in stead of 'hello world 3333' unless cache expired.
  });

Options

const PromiseCache = require('zb-promise-cache');


const simplePromise = function() {
  return new Promise((resolve, reject) => {
    resolve('hello world');
  });
}

const options = {
  'max': 200 // Max lru cache size, default INVINITY
  'maxAge': 100000 // Max cache life time in ms, default, INVINITY
  'debug': true // Display debug msg in console
};

const promiseCache = new PromiseCache(simplePromise, options);

p.get('testing')
  .then(function(val) {
    console.log(val); // 'hello world'

	// Stored in lru cache with max cache size of 200
    // cache life time 100000ms
    // and showing debug logs in console
  });

Functions

/**
 * Get the cached value with cacheKey.
 * If cacheKey does not have value in lru cache,
 * promise will be called with params distributed to the promise called.
 * Value resolved from promise will be stored in lru cache with cacheKey
 * provided and resolved in this function at the same time.
 * @param {Promise} cacheKey -cacheKey that is going to be get the value.
 * @param {array} params - An array of params that will fit into the promise
 *                         in order to retrieve value to be cached when
 *                         there is a cache miss.
 */
get(cacheKey, params)



/**
 * Manually set a value into cacheKey.
 * @param {string} cacheKey - cacheKey that is going to be set with value.
 * @param {any} value - value to be set into cacheKey, default ''.
 */
set(cacheKey, value)



/**
 * Clear all caches.
 */
clear()