Promise Queue

PromiseQueue.js

/**
 * @class PromiseQueue Manage a queue of promises 
 */
function PromiseQueue() {
  const queue = {};
  let idCount = 0;
  return {
    /**
     * Add a promise to the queue and remove it once resolved
     * todo: handle reject()
     * @param {Promise} promise
     * @returns {string} id a unique id of a promise so you could get or remove it manually
     */
    add(promise) {
      const id = `promise_${idCount++}`;
      queue[id] = promise;
      console.log('PromiseQueue.add', Object.keys(queue));
      promise
        .then(() => this.remove(id))
        .catch(() => this.remove(id));
      return id;
    },
    /**
     * Remove a promise from the queue by id
     * @param {string} id
     */
    remove(id) {
      delete queue[id]; 
      console.log('PromiseQueue.remove', Object.keys(queue));
    },
    /**
     * Get a promise from the queue
     * @param {string} id
     * @returns {Promise|undefined}
     */
    get(id) {
      return queue[id];
    },
    /**
     * Invoke a function when all the promises in the queue are resolved or rejected
     * @param {function} onResolve 
     * @param {function} [onReject] silent fail if not defined
     * @returns {Promise}
     */
    then(onResolve, onReject = () => {}) {
      return Promise.all(Object.values(queue))
        .then(onResolve)
        .catch(onReject);
    }
  };
}