get-unique-strings-from-api.js

// no way to reset, at the moment
const get = (() =>{
  let counter = 0;

  return (url) => {
    return new Promise((resolve, reject) => {
      if(counter > 100) {
        reject(false);
      } 

      counter++;
      let request = new XMLHttpRequest();
      request.open("GET", url);
      request.onload = function () {
        if (this.status >= 200 && this.status < 300) {
        resolve(request.response);
        } else {
        reject({
          status: this.status,
          statusText: request.statusText
        });
        }
      };
      request.onerror = function () {
        reject({
        status: this.status,
        statusText: request.statusText
        });
      };
      request.send();
    });
  }
})();


const solve = (url, requiredResultCount) => {
  return new Promise((resolve, reject) => {
    const messages = new Set();

    const again = () => setTimeout(() => {
      get(url)
        .then(res => messages.add(res))
        .catch(console.warn)
        .then(() => {
          if (messages.size !== requiredResultCount) {
            again();
          } else {
            resolve(Array.from(messages));
          }
        });
    }, 0);

    again();
  });
}

const API = 'https://api.github.com/zen'; 
console.log(solve(API, 3));