A quick implementation of Promise.any that does not modify the Promise prototype

anyPromise.js

class AnyPromise {
  constructor(promises) {
    this.promises = promises;
    this.successes = [];
    this.errors = [];
    this.thenCallback = () => { console.error('then not defined'); };
    this.catchCallback = () => { console.error('catch not defined'); };
    this.finallyCallback = () => {};
    this.awaitPromises();
  }

  then(callback) { this.thenCallback = callback; return this; }

  catch(callback) { this.catchCallback = callback; return this; }

  finally(callback) { this.finallyCallback = callback; return this; }

  awaitPromises() {
    this.promises.forEach((promise) => {
      promise
        .then(result => this.successes.push(result))
        .catch(result => this.errors.push(result))
        .finally(() => {
          const finishedLength = this.successes.length + this.errors.length;
          if (finishedLength === this.promises.length) {
            this.executeCallbacks();
          }
        });
    });
  }

  executeCallbacks() {
    if (this.successes.length > 0) {
      this.thenCallback(this.successes);
    } else {
      this.catchCallback(this.errors);
    }
    this.finallyCallback(this.successes, this.errors);
  }
}

const testPromiseFunc = (time, bool) => new Promise((resolve, reject) => {
  setTimeout(() => {
    if (bool) resolve();
    else reject();
  }, time);
});

new AnyPromise([
  testPromiseFunc(500, true),
  testPromiseFunc(1700, false),
  testPromiseFunc(500, true),
])
  .then(console.log.bind(this, 'yay :)'))
  .catch(console.error.bind(this, 'nay :('))
  .finally(console.log.bind(this, 'I\'m done with this!'));

Kudos to @johman10 who paired this with me!