extendsBuiltIn.js

'use strict';

class FetchDataManagerSingleton extends Map {
    static get [Symbol.species]() {
        return Map;
    }

    constructor() {
        this.fetchCount = 0;
        this.timeTilNextFetch = 5000;
    }

    static updateTimeTilNextFetch(newValue) {
        this.timeTilNextFetch = newValue;
    }

    show() {
        console.log(this.entries());
    }
}

module.exports = new FetchDataManagerSingleton();