'use strict';

// Facade that wraps Map and Node.js Timers to provide a simple interface for a

// collection with values that have expiration timeout.

const TimeoutCollection = function (timeout) {

this.timeout = timeout;

this.collection = new Map();

this.timers = new Map();

};

TimeoutCollection.prototype.set = function (key, value) {

const timer = this.timers.get(key);

if (timer) clearTimeout(timer);

const timeout = setTimeout(() => {

this.delete(key);

}, this.timeout);

timeout.unref();

this.collection.set(key, value);

this.timers.set(key, timeout);

};

TimeoutCollection.prototype.get = function (key) {

return this.collection.get(key);

};

TimeoutCollection.prototype.delete = function (key) {

const timer = this.timers.get(key);

if (timer) {

clearTimeout(timer);

this.collection.delete(key);

this.timers.delete(key);

}

};

TimeoutCollection.prototype.toArray = function () {

return [...this.collection.entries()];

};

// Usage

const hash = new TimeoutCollection(1000);

hash.set('uno', 1);

console.dir({ array: hash.toArray() });

hash.set('due', 2);

console.dir({ array: hash.toArray() });

setTimeout(() => {

hash.set('tre', 3);

console.dir({ array: hash.toArray() });

setTimeout(() => {

hash.set('quattro', 4);

console.dir({ array: hash.toArray() });

}, 500);

}, 1500);