priority-events

Event emitter built on top of fastpriorityqueue

const EventEmitter = require('priority-events')

class Cat extends EventEmitter {
  meow (n) {
    this.emit('meow', `m${'e'.repeat(n)}ow`)
  }
}

const cat = new Cat()

cat.on('meow', msg => {
  console.log(msg)
}, 1)

cat.on('meow', msg => {
  console.log('Your cat meows!')
}, 666)

cat.meow(6)
// Your cat meows
// meeeeeeow

To explain it really simple: I had to have an prioritized event emitter so I wrote one myself. It tries to imitate node events API as well as I could do it.

Usage

Listener registration

Everything is the same as in the node's events module except for listener registration.

ee.on(eventName, listener, priority)

By default priority is set to 1 but you can set it from -Infinity to Infinity

Emitting events

When you call ee.emit() all listeners are called from the highest priority to the lowest one.

You can stop execution of the listeners by returning false in one of the listeners:

let counter = 0

ee.on('event', () => {
  counter += 1
  return false
}, 2)

ee.on('event', () => {
  counter += 1
}, 1)

counter // 1