mysql2/lib/promise/inherit_events.js

fast mysql driver. Implements core protocol, prepared statements, ssl and compression in native JS

'use strict';

function inheritEvents(source, target, events) {
  const listeners = {};
  target
    .on('newListener', (eventName) => {
      if (events.indexOf(eventName) >= 0 && !target.listenerCount(eventName)) {
        source.on(
          eventName,
          (listeners[eventName] = function () {
            const args = [].slice.call(arguments);
            args.unshift(eventName);

            target.emit.apply(target, args);
          })
        );
      }
    })
    .on('removeListener', (eventName) => {
      if (events.indexOf(eventName) >= 0 && !target.listenerCount(eventName)) {
        source.removeListener(eventName, listeners[eventName]);
        delete listeners[eventName];
      }
    });
}

module.exports = inheritEvents;