Get a promise that resolves/rejects when the specified `accepted` or `rejected` events are received.

eventPromise.js

const EventEmitter = require('events');

const event = new EventEmitter();

// THIS IS THE IMPORTANT BIT
const eventPromise = (accepted, rejected, acceptMessage = '', rejectMessage = '') => new Promise((resolve, reject) => {
  event.on(accepted, (...args) => {
    event.removeAllListeners(accepted);
    event.removeAllListeners(rejected);

    resolve([acceptMessage, ...args]);
  });

  event.on(rejected, (...args) => {
    event.removeAllListeners(accepted);
    event.removeAllListeners(rejected);

    reject([rejectMessage, ...args]);
  });
});

// FROM HERE ON IT'S JUST A DEMONSTRATION
function test(code) {
  const testValue = Math.random();
  const pass = testValue > 0.7;

  setTimeout(() => {
    event.emit(`${pass ? 'accepted' : 'rejected'}-${code}`, testValue);
  }, 200 + Math.random() * 1000);
};

const wait = async () => {
  try {
    const numbers = (new Array(100)).fill(0).map((_a, i) => i);

    const promises = await Promise.allSettled(
      numbers.map((number) => {
        test(number);
        return eventPromise(
          `accepted-${number}`,
          `rejected-${number}`,
          `ACCEPTED EVENT ${number}`,
          `REJECTED EVENT ${number}`,
        );
      })
    );

    console.table(promises);
  } catch (error) {
    console.log(error);
  }
}

wait();