on-one

Subscribe to one or more events and accept the first emitted.

npm install on-one

var EventEmitter = require('events').EventEmitter;
var onOne = require('on-one');
var emitter = new EventEmitter();

onOne(emitter, ['error', 'finish'], function (err, eventName) {
  if (eventName === 'error') {
    console.error('Stream failed:', err);
  } else {
    console.log('Stream finished successfully');
  }
});

emitter.emit('finish'); // logs the success message

The callback receives the error event's error as its first argument. Other events pass null, followed by their event arguments and the event name. After the first event, all listeners installed by onOne are removed.